mercury/NEWS.md

NEWS since Mercury 22.01

Changes that may break compatibility

• The predicates read_term/3, read_term/4, read_term_with_op_table/4, read_term_with_op_table/5 have been removed from the term_io module of the Mercury standard library.

• The order of two arguments in the predicates write_variable/4, write_variable/5, write_variable_with_op_table/4, and write_variable_with_op_table/5 in the term_io module has been swapped.

• The io module is being reorganized. Some predicates have been marked as obsolete, while other predicates that had been marked as obsolete before the release of Mercury 22.01 have been removed.

• The old random number generator in the random module has been removed.

• The system of operator priorities in the ops module has been inverted. Previously, given two operators of different priorities, the one that bound more tightly was the one with the lower numerical priority. Now, operators with higher numerical priorities bind more tightly. There are other changes as well, such as priorities no longer being interchangeable with other integers, some types and function symbols being renamed, and an updated op_table type class with a somewhat different list of methods.

  The old contents of the ops module is still available as extras/old_library_modules/old_ops.

• The mercury_term_parser module now expects the operator table to be specified using the updated op_table type class in the new ops module.

  The old contents of the mercury_term_parser module is still available as extras/old_library_modules/old_mercury_term_parser.

• The enum/1 typeclass has been modified by having its from_int method changed from a semidet function of arity one (plus the return value) to a semidet predicate of arity two.

• The sparse_bitset, fat_sparse_bitset and tree_bitset modules now require the items in those sets to be instances of the uenum typeclass, not the enum typeclass.

• The digraph_key type in the digraph module is now an instance of the uenum typeclass, not the enum typeclass.

• Six predicates in the injection module, det_insert/4, det_set/4, det_update/4, insert/4, set/4 and update/4, have had the order of their arguments changed.

• Two predicates in the bt_array module, resize/4 and shrink/4, have had the order of their arguments changed.

• One predicate in the ranges module, nondet_member/2, has had the order of its arguments changed.

• The character sequences <<u and >>u are now recognized as single tokens. (They are the names of new versions of the left and right shift operators that expect the shift amount to be specified by an unsigned integer; previously, shift amounts were always specified by signed integers.) This means that existing code in which a << or >> operator was followed immediately, without an intervening space, by a u character, will now be parsed differently.

• The compiler no longer accepts : as the module name separator in backquoted operators. (Mercury switched to using . as the module name separator around 2003.)

• The compiler now ignores comments when warning about unused arguments in foreign_proc pragmas. Warnings can no longer be suppressed by mentioning a variable in a comment; use a leading underscore to mark intentionally unused variables. This change also prevents spurious warnings about return statements caused by the word return appearing only in comments.

• We have dropped support for the x86 (32-bit) version of Cygwin.

• We have dropped support for versions of MSVC before version 19.3 (Visual Studio 2022).

• The --use-subdirs and --use-grade-subdirs options now cause .mh files to be placed in a Mercury/mhs subdirectory instead of the current directory. This reduces clutter in the current directory, but may require additional options to be passed to the C compiler in order for it to find those header files.

• We have changed the meaning of mmc --make name.cs.

  The mmc --make target name.cs now means "build the .cs file of the named module". To build all the .c files of a program, which was the previous meaning of that target, use the target program.all_cs.

• Some (undocumented) mmake variables in compiler-generated .dv files have been renamed:

    program.cs          -> program.all_cs
    program.os          -> program.all_os
    program.pic_os      -> program.all_pic_os
    program.javas       -> program.all_javas
    program.css         -> program.all_css
  
    program.all_mhs     -> program.mhs_to_clean
    program.all_mihs    -> program.mihs_to_clean
    program.all_int0s   -> program.int3s_to_clean
  

• We have replaced the --no-warn-only-one-format-string-error compiler option with the new option named --warn-all-format-string-errors.

• We have disabled support for concurrency in non-parallel low-level C grades. It was never useful for anything other than trivial programs.

Changes to the Mercury standard library

Changes to the array module

• The following predicates and functions have been added:

  • pred semidet_least_index/2
  • pred semidet_greatest_index/2
  • func uinit/2
  • pred uinit/3
  • func ugenerate/3
  • pred ugenerate_foldl/5
  • pred ugenerate_foldl2/7
  • func ulookup/2
  • pred ulookup/3
  • pred semidet_ulookup/3
  • pred unsafe_ulookup/3
  • func uelem/2
  • func unsafe_uelem/2
  • func uset/3
  • pred uset/4
  • pred semidet_uset/4
  • pred unsafe_uset/4
  • func uelem :=/3
  • func unsafe_uelem :=/3
  • pred uswap/4
  • pred unsafe_uswap/4
  • func umin/1
  • pred umin/2
  • func umax/1
  • pred umax/2
  • pred ubounds/3
  • func usize/1
  • pred usize/2
  • pred in_ubounds/2
  • func uresize/3
  • pred uresize/4
  • func ushrink/2
  • pred ushrink/3
  • pred fill_urange/5

• The following predicates have been removed:

  • pred random_permutation/4 (replacement: random.shuffle_array/4 or random.shuffle_array/5)

  • pred sort_fix_2014/0 (no replacement needed)

• The following function has been marked obsolete:

  • func array_to_doc/1 (replacement: pretty_printer.array_to_doc/1)

Changes to the bag module

• The following predicates and functions have been added:

  • func ucount/1
  • func ucount_unique/1
  • func ucount_value/2
  • pred ucount_value/3

Changes to the benchmarking module

• The following predicates have been added:

  • pred full_memory_stats_are_available/0
  • pred report_stats/3
  • pred report_stats/4
  • pred report_standard_stats/2
  • pred report_standard_stats/3
  • pred report_full_memory_stats/2
  • pred report_full_memory_stats/3
  • pred report_tabling_statistics/2
  • pred report_tabling_statistics/3

• The following predicates have been marked obsolete:

  • pred report_stats/0
  • pred report_full_memory_stats/0

Changes to the bitmap module

• The following predicates have been added:

  • pred num_bytes/2
  • pred from_string/2
  • pred read_bitmap/6
  • pred read_bitmap/7
  • pred read_bitmap_range/8
  • pred read_bitmap_range/9
  • pred write_bitmap/3
  • pred write_bitmap/4
  • pred write_bitmap_range/5
  • pred write_bitmap_range/6

Changes to the bt_array module

• The following predicates have had the order of their arguments changed:

  • pred resize/4
  • pred shrink/4

Changes to the builtin module

• The following obsolete predicate and function have been removed:

  • func promise_only_solution/1
  • pred promise_only_solution_io/4

Changes to the char module

• The following type has had its typeclass memberships changed:

  • The type character is now an instance of the new uenum typeclass.

• The following predicate and functions have been added:

  • func to_uint/1
  • pred from_uint/2
  • func det_from_uint/1

• The following function has been marked obsolete:

  • func char_to_doc/1 (replacement: pretty_printer.char_to_doc/1)

Changes to the construct module

• The following predicates have been added:

  • pred num_functors/2
  • pred get_functor_ordinal/3
  • pred get_functor_lex/3
  • pred construct/4

Changes to the cord module

• The following predicates have been added:

  • pred is_non_empty/1
  • pred foldr2/6
  • pred foldr3/8
  • pred head/2
  • pred is_singleton/2
  • pred cons_list/2
  • pred snoc_list/2

Changes to the counter module

• The following type has been added:

  • type ucounter/0

• The following predicate and function have been added:

  • func uinit/1
  • pred uinit/2
  • pred uallocate/1

Changes to the diet module

• The following functions and predicates have been added:

  • func from_sorted_list/1
  • pred nondet_member/2
  • func ucount/1

• The following obsolete predicate has been removed:

  • pred empty/1

Changes to the digraph module

• The following type has had its typeclass memberships changed:

  • The digraph_key(T) type is now an instance of the uenum typeclass, and is no longer an instance of the enum typeclass.

• The following predicates and functions have been added:

  • func symmetric_closure/1 (synonym for sc/1)
  • func transitive_closure/1 (synonym for tc/1)
  • func reflexive_transitive_closure/1 (synonym for rtc/1)
  • pred reachable_vertices_from/3

• We have improved the implementations of transitive closure and reflexive transitive closure.

New edit_distance module

• This new module defines operations that, when given a query sequence and a set of candidate sequences, finds out which candidate sequence is closest to the query sequence, in terms of the configurable distances added by operations such as inserting or replacing elements in sequences.

Changes to the edit_seq module

• This module deals with many integers, including row numbers, column numbers, and operation costs, that cannot be negative. To ensure that this restriction is enforced automatically, we have changed the types of all these integers from int to uint.

Changes to the enum module

• The following typeclass has been modified:

  • The enum/1 typeclass has had its from_int method changed from a semidet function of arity one (plus the return value) to a semidet predicate of arity two.

• The following typeclass has been added:

  • typeclass uenum/1

• The following functions have been added:

  • func from_int/1 (replaces class method; born obsolete)
  • func det_from_uint/1

Changes to the fat_sparse_bitset module

• The following type has had its typeclass memberships changed:

  • The fat_sparse_bitset(T) type now requires T to be an instance of the uenum typeclass, replacing the earlier requirement that it be a member of the enum typeclass.

• The documentation of the following predicates and functions have been clarified:

  • func sorted_list_to_set/1
  • pred sorted_list_to_set/2

• The following functions and predicates have been added:

  • func from_list/1
  • func from_sorted_list/1
  • func ucount/1
  • pred nondet_member/1

• The following obsolete predicate has been removed:

  • pred empty/1

New fatter_sparse_bitset module

• This new module defines a more compact version of the data structure defined by the fat_sparse_bitset module, and implements the same set of operations on this data structure.

Changes to the float module

• The following function has been marked obsolete:

  • func float_to_doc/1 (replacement: pretty_printer.float_to_doc/1)

Changes to the getopt module

• The following predicates have been added:

  • pred recognize_options/7
  • pred recognize_all_options/7

• The following predicate has been marked obsolete:

  • pred record_arguments/7 (replacement: getopt.recognize_options/7)

Changes to the hash_table module

• The following predicate has been added:

  • pred lookup/3

• The following obsolete predicates have been removed:

  • pred char_hash/2
  • pred float_hash/2
  • pred generic_hash/2
  • pred int_hash/2
  • pred string_hash/2
  • pred uint_hash/2

Changes to the injection module

• The following predicates have had the order of their arguments changed:

  • pred det_insert/4
  • pred det_set/4
  • pred det_update/4
  • pred insert/4
  • pred set/4
  • pred update/4

Changes to the int module

• The following type has had its typeclass memberships changed:

  • The type int is now an instance of the new uenum typeclass.

• The following predicates and functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2
  • func ubits_per_int/0
  • pred ubits_per_int/1

• The following function has been marked obsolete:

  • func int_to_doc/1 (replacement: pretty_printer.int_to_doc/1)

Changes to the int8 module

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2

• The following function has been marked obsolete:

  • func int8_to_doc/1 (replacement: pretty_printer.int8_to_doc/1)

Changes to the int16 module

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2

• The following function has been marked obsolete:

  • func int16_to_doc/1 (replacement: pretty_printer.int16_to_doc/1)

Changes to the int32 module

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2

• The following function has been marked obsolete:

  • func int32_to_doc/1 (replacement: pretty_printer.int32_to_doc/1)

Changes to the int64 module

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2

• The following function has been marked obsolete:

  • func int64_to_doc/1 (replacement: pretty_printer.int64_to_doc/1)

Changes to the io module

• The following predicates and functions have been added:

  • pred make_io_error_from_system_error/5
  • pred make_io_error_from_windows_error/5
  • pred get_errno_error/2
  • pred get_exception_object_error/2
  • pred get_system_error/2
  • pred get_system_error_name/2
  • pred get_windows_error/2
  • func init_posn/0
  • pred read_file_as_string_wf/3
  • pred read_file_as_string_wf/4
  • pred read_file_as_string_and_num_code_units_wf/3
  • pred read_file_as_string_and_num_code_units_wf/4
  • pred read_named_file_as_string_wf/4
  • pred read_named_file_as_lines_wf/4
  • pred system_error_is_success/1
  • pred write_binary_string_utf8/3
  • pred write_binary_string_utf8/4
  • pred write_prefixed_lines/4
  • pred write_prefixed_lines/5

• The following obsolete predicates have been removed:

  • pred see/3 (replacement: prolog.see/3)
  • pred see_binary/3 (replacement: prolog.see_binary/3)
  • pred seen/2 (replacement: prolog.seen/2)
  • pred seen_binary/2 (replacement: prolog.seen_binary/2)
  • pred tell/4 (replacement: prolog.tell/4)
  • pred tell_binary/4 (replacement: prolog.tell_binary/4)
  • pred told/2 (replacement: prolog.told/2)
  • pred told_binary/2 (replacement: prolog.told_binary/2)

• The following predicates have been marked obsolete:

  • pred read_bitmap/6 (replacement: bitmap.read_bitmap/6)

  • pred read_bitmap/7 (replacement: bitmap.read_bitmap/7)

  • pred read_bitmap/8 (replacement: bitmap.read_bitmap_range/8)

  • pred read_bitmap/9 (replacement: bitmap.read_bitmap_range/9)

  • pred write_bitmap/3 (replacement: bitmap.write_bitmap/3)

  • pred write_bitmap/4 (replacement: bitmap.write_bitmap/4)

  • pred write_bitmap/5 (replacement: bitmap.write_bitmap_range/5)

  • pred write_bitmap/6 (replacement: bitmap.write_bitmap_range/6)

  • pred report_stats/3 (replacement: benchmarking.report_stats/3)

  • pred report_stats/4 (replacement: benchmarking.report_stats/4)

  • pred report_standard_stats/2 (replacement: benchmarking.report_standard_stats/2)

  • pred report_standard_stats/3 (replacement: benchmarking.report_standard_stats/3)

  • pred report_full_memory_stats/2 (replacement: benchmarking.report_full_memory_stats/2)

  • pred report_full_memory_stats/3 (replacement: benchmarking.report_full_memory_stats/3)

  • pred report_tabling_statistics/2 (replacement: benchmarking.report_tabling_statistics/2)

  • pred report_tabling_statistics/3 (replacement: benchmarking.report_tabling_statistics/3)

  • pred remove_file/4 (replacement: io.file.remove_file/4)

  • pred remove_file_recursively/4 (replacement: io.file.remove_file_recursively/4)

  • pred rename_file/5 (replacement: io.file.rename_file/5)

  • pred have_symlinks/0 (replacement: io.file.have_symlinks/0)

  • pred make_symlink/5 (replacement: io.file.make_symlink/5)

  • pred read_symlink/4 (replacement: io.file.read_symlink/4)

  • pred check_file_accessibility/5 (replacement: io.file.check_file_accessibility/5)

  • pred file_type/5 (replacement: io.file.file_type/5)

  • pred file_modification_time/4 (replacement: io.file.file_modification_time/4)

  • pred make_temp_file/3 (replacement: io.file.make_temp_file/3)

  • pred make_temp_file/6 (replacement: io.file.make_temp_file/6)

  • pred make_temp_directory/3 (replacement: io.file.make_temp_directory/3)

  • pred make_temp_directory/6 (replacement: io.file.make_temp_directory/6)

  • pred have_make_temp_directory/0 (replacement: io.file.have_make_temp_directory/0)

  • pred get_temp_directory/3 (replacement: io.file.get_temp_directory/3)

  • pred get_environment_var/4 (replacement: io.environment.get_environment_var/4)

  • pred set_environment_var/5 (replacement: io.environment.set_environment_var/5)

  • pred set_environment_var/4 (replacement: io.environment.set_environment_var/4)

  • pred have_set_environment_var/0 (replacement: io.environment.have_set_environment_var/0)

  • pred get_environment_var_map/3 (replacement: io.environment.get_environment_var_map/3)

  • pred call_system/4 (replacement: io.call_system.call_system/4)

  • pred call_system_return_signal/4 (replacement: io.call_system.call_system_return_signal/4)

  • pred get_globals/3 (replacement: a user-defined mutable)

  • pred set_globals/3 (replacement: a user-defined mutable)

  • pred update_globals/3 (replacement: a user-defined mutable)

  • pred input_stream_foldl/5 (replacement: stream.input_stream_fold/6)

  • pred input_stream_fold/6 (replacement: stream.input_stream_fold/6)

  • pred input_stream_foldl_io/4 (replacement: stream.input_stream_fold_state/5)

  • pred input_stream_foldl_io/5 (replacement: stream.input_stream_fold_state/5)

  • pred input_stream_foldl2_io/5 (replacement: stream.input_stream_foldl_state/6)

  • pred input_stream_foldl2_io/6 (replacement: stream.input_stream_fold_state/6)

  • pred input_stream_foldl2_io_maybe_stop/5 (replacement: stream.input_stream_fold2_state_maybe_stop/6)

  • pred binary_input_stream_foldl/5 (replacement: stream.input_stream_fold/6)

  • pred binary_input_stream_foldl/6 (replacement: stream.input_stream_fold/6)

  • pred binary_input_stream_foldl_io/4 (replacement: stream.input_stream_fold_state/5)

  • pred binary_input_stream_foldl2_io/5 (replacement: stream.input_stream_fold2_state/6)

  • pred binary_input_stream_foldl2_io/6 (replacement: stream.input_stream_fold2_state/6)

  • pred binary_input_stream_foldl2_io_maybe_stop/5 (replacement: stream.input_stream_fold2_state_maybe_stop/6)

  • pred binary_input_stream_foldl2_io_maybe_stop/6 (replacement: stream.input_stream_fold2_state_maybe_stop/6)

New io.call_system module

• This new module has these predicates and functions:

  • pred call_system/4
  • pred call_system_return_signal/4
  • func decode_system_command_exit_code/1

New io.environment module

• This new module has these predicates:

  • pred get_environment_var/4
  • pred set_environment_var/5
  • pred set_environment_var/4
  • pred have_set_environment_var/0
  • pred get_environment_var_map/3

New io.file module

• This new module has these predicates:

  • pred remove_file/4
  • pred remove_file_recursively/4
  • pred rename_file/5
  • pred have_symlinks/0
  • pred make_symlink/5
  • pred read_symlink/4
  • pred check_file_accessibility/5
  • pred file_type/5
  • pred file_modification_time/4
  • pred make_temp_file/3
  • pred make_temp_file/6
  • pred make_temp_directory/3
  • pred make_temp_directory/6
  • pred have_make_temp_directory/0
  • pred get_temp_directory/3

Changes to the library module

• The following functions have been added:

  • func architecture/0
  • func mercury_version/0
  • func package_version/0

Changes to the list module

• The following predicates and functions have been added:

  • pred chunk_foldl/5
  • pred chunk_foldl2/7
  • pred chunk_foldl3/9
  • pred chunk_foldl4/11
  • pred gap_foldl/5
  • pred head/2
  • pred tail/2
  • pred det_head/2
  • pred det_tail/2
  • func inst_preserving_condense/1
  • func intersect/2
  • pred intersect/3
  • func intersect_lists/1
  • pred intersect_lists/2
  • pred intersperse/3
  • pred intersperse_list/3
  • pred intersperse_list_last/4
  • pred is_non_empty/1
  • pred is_singleton/2
  • pred last_gap_foldl/6
  • func map_corresponding4/5
  • pred map_corresponding4/6
  • func merge_lists/1
  • func merge_lists/2
  • pred merge_lists/2
  • pred merge_lists/3
  • func merge_lists_and_remove_dups/1
  • func merge_lists_and_remove_dups/2
  • pred merge_lists_and_remove_dups/2
  • pred merge_lists_and_remove_dups/3
  • pred nondet_member/2
  • pred remove_prefix/3
  • func take_while_not/2
  • pred take_while_not/3
  • pred take_while_not/4
  • func ulength/1
  • pred ulength/2

• The following function has been marked obsolete:

  • func list_to_doc/1 (replacement: pretty_printer.list_to_doc/1)

Changes to the map module

• The following predicates and functions have been added:

  • pred is_non_empty/1
  • pred max_key/2
  • pred min_key/2
  • pred compose_maps/3
  • pred sorted_keys_match/2
  • func ucount/1
  • pred ucount/2

• We have added cc_multi versions of many of the higher-order predicates in this module.

Changes to the mercury_term_lexer module

• The representation type of the tokens returned has been tightened. Previously, the documented type of tokens contained two function symbols that were needed only by the implementation of the lexer, and could never be returned in the generated token lists. The new definition differs from the old one only in the fact that it omits these two function symbols.

Changes to the multi_map module

• The following predicates and functions have been added:

  • func all_ucount/1
  • pred all_ucount/2
  • func get_values_for_key/2
  • func ucount/1
  • pred ucount/2

Changes to the one_or_more module

• The following predicates and functions have been added:

  • pred is_non_empty/1
  • pred nondet_member/2
  • func ulength/1
  • pred ulength/2

• The following function has been marked obsolete:

  • func one_or_more_to_doc/1 (replacement: pretty_printer.one_or_more_to_doc/1)

Changes to the one_or_more_map module

• The following predicates and functions have been added:

  • func all_ucount/1
  • pred all_ucount/2
  • func get_values_for_key/2
  • func reverse_add/3
  • pred reverse_add/4
  • func ucount/1
  • pred ucount/2

Changes to the ops module

• The representation of operator priorities has been changed. Priorities used to be represented as signed integers between 0 and 1200, with higher numbers representing operators that bind less tightly. Priorities are now represented using unsigned integers between 0u and 1500u, with higher numbers representing operators that bind more tightly. To guard against priorities being unintentionally confused with other kinds of numbers, they are now wrapped in the prio function symbol.

• The representation of the set of operators that a string may represent has been changed. Operator tables used to map each operator string (such as "-") to a list of operator descriptions, each of which could be infix, binary prefix, prefix or postfix. This allowed a table entry to declare an operator string to be e.g. an infix operator using two separate entries, with different priorities. Operator tables now map each operator string to a structure which has

  • one slot for a description of an infix operator,
  • one slot for a description of a binary prefix operator,
  • one slot for a description of a unary prefix operator, and
  • one slot for a description of a unary postfix operator.

  Besides making some nonsensical entries that could exist in old op tables unrepresentable, the new op table also allows users of operator information to test more simply and quickly whether an operator string represents e.g. a prefix operator.

• The assoc type has been renamed to arg_prio_gt_or_ge, which reflects its semantics. Its function symbols x and y have been renamed to arg_gt and arg_ge respectively.

• The list of methods in the op_table type class has been changed.

• The method max_priority/1 has been replaced by the method loosest_op_priority/1.

• The method lookup_op/2 has been renamed to is_op/2.

• The new method universal_priority/1 has been added. It is intended to replace uses of max_priority + 1 to denote a context that accept terms using any operator, regardless of its priority.

• The new method tightest_op_priority/1 has been added. It is intended to replace uses of the integer constant 0 as a priority.

• The new method comma_priority/1 has been added. It is intended to denote the priority of the comma character, which separates term arguments, when used as an operator.

• The argument types of the lookup_op_infos/2 method have been changed.

• The following predicates and functions have been added:

  • func decrement_priority/1
  • func increment_priority/1
  • func mercury_op_table_arg_priority/0
  • func mercury_op_table_comma_priority/0
  • func mercury_op_table_loosest_op_priority/0
  • func mercury_op_table_tightest_op_priority/0
  • func mercury_op_table_universal_priority/0
  • pred mercury_op_table_binary_prefix_op/5
  • pred mercury_op_table_infix_op/5
  • pred mercury_op_table_lookup_operator_term/3
  • pred mercury_op_table_postfix_op/4
  • pred mercury_op_table_prefix_op/4
  • pred mercury_op_table_search_binary_prefix_op/4
  • pred mercury_op_table_search_infix_op/4
  • pred mercury_op_table_search_op/1
  • pred mercury_op_table_search_op_infos/3
  • pred mercury_op_table_search_postfix_op/3
  • pred mercury_op_table_search_prefix_op/3
  • func min_priority_for_arg/2
  • pred priority_ge/2
  • pred priority_gt/2
  • pred priority_le/2
  • pred priority_lt/2

• The following predicates have been renamed:

  • pred mercury_op_table_prefix_op/5 to op_infos_prefix_op/5
  • pred mercury_op_table_binary_prefix_op/5 to op_infos_binary_prefix_op/5
  • pred mercury_op_table_infix_op/5 to op_infos_infix_op/5
  • pred mercury_op_table_postfix_op/5 to op_infos_postfix_op/5

Changes to the pqueue module

• The following predicate has been added:

  • pred map_values/3

Changes to the pretty_printer module

• The following predicates and functions have been added:

  • func array_to_doc/1
  • func char_to_doc/1
  • func float_to_doc/1
  • func get_formatter_map_entry_types/1
  • func int_to_doc/1
  • func int8_to_doc/1
  • func int16_to_doc/1
  • func int32_to_doc/1
  • func int64_to_doc/1
  • func list_to_doc/1
  • func one_or_more_to_doc/1
  • func string_to_doc/1
  • func tree234_to_doc/1
  • func uint_to_doc/1
  • func uint8_to_doc/1
  • func uint16_to_doc/1
  • func uint32_to_doc/1
  • func uint64_to_doc/1
  • func version_array_to_doc/1
  • pred write_doc_formatted/3
  • pred write_doc_formatted/4

Changes to the prolog module

• The following predicate has been deleted:

  • pred is/2

New ra_list module

• This new module contains operations on random access lists.

Changes to the random module

• The old random number generator has been removed. It has been replaced by the new type class random number generation framework defined in this module. As a result, the following predicates have been removed:

  • pred init/2
  • pred random/3
  • pred random/5
  • pred randmax/3
  • pred randcount/3
  • pred permutation/4 (replacement: random.shuffle_list/4 or random.shuffle_list/5)

Changes to the ranges module

• The following predicate has had the order of its arguments changed:

  • pred nondet_member/2

• The following predicates and functions have been added:

  • func make_singleton_set/1
  • pred is_singleton/2
  • pred contains/2
  • func count/1
  • pred delete/3
  • pred delete_list/3
  • pred difference/3
  • func intersect/2
  • pred intersect/3
  • pred insert_list/3
  • func list_to_ranges/1
  • pred list_to_ranges/2
  • pred nondet_range_member/3
  • pred restrict_min/3
  • pred restrict_max/3
  • pred restrict_range/4
  • pred search_range/4
  • func set_to_ranges/1
  • pred set_to_ranges/2
  • func ucount/1
  • pred union/3

• The following function and predicate have been marked obsolete:

  • func intersection/2 (replacement: intersect/2)
  • pred range_member/3 (replacement: nondet_range_member/3)

Changes to the rbtree module

• The following predicates and functions have been added:

  • func foldr/3
  • pred foldr/4
  • pred foldr2/6
  • pred foldr_values/4
  • func ucount/1
  • pred ucount/2

Changes to the set module

• The following predicates and functions have been added:

  • pred map2_fold/6
  • pred nondet_member/2
  • func ucount/1
  • pred ucount/2

• The following obsolete predicates and function have been removed:

  • pred empty/1
  • pred non_empty/1
  • func set/1

Changes to the set_bbbtree module

• The following predicates and functions have been added:

  • pred nondet_member/2
  • func ucount/1
  • pred ucount/2

• The following obsolete predicates have been removed:

  • pred empty/1
  • pred non_empty/1
  • pred nondet_member/2

Changes to the set_ctree234 module

• The following predicates and functions have been added:

  • func from_sorted_list/1
  • pred nondet_member/2
  • pred power_intersect/2
  • func ucount/1

• The following predicate has been marked obsolete:

  • pred one_member/2 (replacement: nondet_member/2)

• The following obsolete predicates have been removed:

  • pred empty/1
  • pred non_empty/1

Changes to the set_ordlist module

• The following predicates and functions have been added:

  • pred nondet_member/2
  • func ucount/1
  • pred ucount/2

• The following obsolete predicates have been removed:

  • pred empty/1
  • pred non_empty/1

Changes to the set_tree234 module

• The following predicates and functions have been added:

  • func from_sorted_list/1
  • pred nondet_member/2
  • func ucount/1

• The following obsolete predicates have been removed:

  • pred empty/1
  • pred non_empty/1

Changes to the set_unordlist module

• We have changed the behaviour of the (out, in) is nondet mode of the predicate member/2 so that it does not return any element of the set more than once.

• The following predicates and functions have been added:

  • pred nondet_member/2
  • func ucount/1
  • pred ucount/2

• The following obsolete predicates have been removed:

  • pred empty/1
  • pred non_empty/1

Changes to the sparse_bitset module

• The following type has had its typeclass memberships changed:

  • The sparse_bitset(T) type now requires T to be an instance of the uenum typeclass, replacing the earlier requirement that it be a member of the enum typeclass.

• The following predicates and functions have been added:

  • func from_list/1
  • func from_sorted_list/1
  • pred nondet_member/2
  • func ucount/1

• The following obsolete predicate has been removed:

  • pred empty/1

• The documentation of the following predicates and functions have been clarified:

  • func sorted_list_to_set/1
  • pred sorted_list_to_set/2

Changes to the std_util module

• We have changed the behaviour of pow/3 so that it throws an exception if it is called with a negative integer as its second argument.

Changes to the string module

• The following predicates and functions have been added:

  • func add_prefix/2
  • func between_code_points/3
  • pred between_code_points/4
  • pred check_well_formedness/2
  • pred code_point_offset/3
  • pred code_point_offset/4
  • pred contains_match/2
  • func count_code_points/1
  • pred count_code_points/2
  • pred find_first_char/3
  • pred find_first_char_start/4
  • pred find_last_char/3
  • func internal_string_encoding/0
  • func left_by_code_point/2
  • pred left_by_code_point/3
  • func right_by_code_point/2
  • pred right_by_code_point/3
  • pred split_by_code_point/3
  • pred split_by_code_point/4
  • pred replace_all_sv/4
  • pred unsafe_find_first_char_start/4

• The following obsolete modes have been removed from the following predicates:

  • pred to_char_list(uo, in)
  • pred to_rev_char_list(in, out)
  • pred append(out, out, in)
  • pred prefix(in, out)
  • pred suffix(in, out)

• The following predicates and functions have been marked obsolete:

  • func string_to_doc/1 (replacement: pretty_printer.string_to_doc/1)
  • func between_codepoints/3 (replacement: between_code_points/3)
  • pred between_codepoints/4 (replacement: between_code_points/4)
  • pred codepoint_offset/3 (replacement: code_point_offset/3)
  • pred codepoint_offset/4 (replacement: code_point_offset/4)
  • func count_codepoints/1 (replacement: count_code_points/1)
  • pred count_codepoints/2 (replacement: count_code_points/2)
  • func left_by_codepoint/2 (replacement: left_by_code_point/2)
  • pred left_by_codepoint/3 (replacement: left_by_code_point/3)
  • func right_by_codepoint/2 (replacement: right_by_code_point/2)
  • pred right_by_codepoint/3 (replacement: right_by_code_point/3)
  • pred split_by_codepoint/3 (replacement: split_by_code_point/3)
  • pred split_by_codepoint/4 (replacement: split_by_code_point/4)

• The semantics of the format_table_max function has been changed. Previously, the function's documentation was silent on how the returned string would be constructed if some columns contained strings that exceeded that column's maximum width. What it actually did was to split the line at the end of the too-long columns, continuing the row in the next line at the expected initial column. Since splitting the line is probably not what users of this function expect, we have now changed this function to never break a row into more than one line. We have also documented this behavior.

Changes to the string.builder module

• The following predicates and functions have been added:

  • pred append_char/3
  • pred append_string/3
  • pred append_strings/3
  • pred append_strings_sep/4
  • pred format/4
  • func total_num_code_points/1
  • pred total_num_code_points_is_at_most/2

Changes to the term module

• The following type has had its typeclass memberships changed:

  • The type var/1 is now an instance of the new uenum typeclass.

• The following predicates have been marked obsolete:

  • pred generic_term/1 (replacement: with_type annotations on expressions)

  • pred decimal_term_to_int/2 (replacement: term_int.decimal_term_to_int/2)

  • pred term_to_int/2 (replacement: term_int.term_to_int/2)

  • pred term_to_int8/2 (replacement: term_int.term_to_int8/2)

  • pred term_to_int16/2 (replacement: term_int.term_to_int16/2)

  • pred term_to_int32/2 (replacement: term_int.term_to_int32/2)

  • pred term_to_int64/2 (replacement: term_int.term_to_int64/2)

  • pred term_to_uint/2 (replacement: term_int.term_to_uint/2)

  • pred term_to_uint8/2 (replacement: term_int.term_to_uint8/2)

  • pred term_to_uint16/2 (replacement: term_int.term_to_uint16/2)

  • pred term_to_uint32/2 (replacement: term_int.term_to_uint32/2)

  • pred term_to_uint64/2 (replacement: term_int.term_to_uint64/2)

  • func int_to_decimal_term/2 (replacement: term_int.int_to_decimal_term/2)

  • func int8_to_decimal_term/2 (replacement: term_int.int8_to_decimal_term/2)

  • func int16_to_decimal_term/2 (replacement: term_int.int16_to_decimal_term/2)

  • func int32_to_decimal_term/2 (replacement: term_int.int32_to_decimal_term/2)

  • func int64_to_decimal_term/2 (replacement: term_int.int64_to_decimal_term/2)

  • func uint_to_decimal_term/2 (replacement: term_int.uint_to_decimal_term/2)

  • func uint8_to_decimal_term/2 (replacement: term_int.uint8_to_decimal_term/2)

  • func uint16_to_decimal_term/2 (replacement: term_int.uint16_to_decimal_term/2)

  • func uint32_to_decimal_term/2 (replacement: term_int.uint32_to_decimal_term/2)

  • func uint64_to_decimal_term/2 (replacement: term_int.uint64_to_decimal_term/2)

  • pred occurs/3 (replacement: term_subst.var_occurs_in_subst_term/2)

  • pred occurs_list/3 (replacement: term_subst.var_occurs_in_subst_terms/2)

  • pred is_ground/1 (replacement: term_subst.term_is_ground/1)

  • pred is_ground_in_bindings/2 (replacement: term_subst.term_is_ground_in_bindings/2)

  • pred rename_var_in_term/4 (replacement: term_subst.rename_var_in_term/4)

  • pred rename_var_in_terms/4 (replacement: term_subst.rename_var_in_terms/4)

  • pred apply_renaming_in_var/3 (replacement: term_subst.apply_renaming_in_var/3)

  • pred apply_renaming_in_vars/3 (replacement: term_subst.apply_renaming_in_vars/3)

  • pred apply_renaming_in_term/3 (replacement: term_subst.apply_renaming_in_term/3)

  • pred apply_renaming_in_terms/3 (replacement: term_subst.apply_renaming_in_terms/3)

  • pred substitute_var_in_term/4 (replacement: term_subst.substitute_var_in_term/4)

  • pred substitute_var_in_terms/4 (replacement: term_subst.substitute_var_in_terms/4)

  • pred substitute_corresponding_in_term/3 (replacement: term_subst.substitute_corresponding_in_term/3)

  • pred substitute_corresponding_in_terms/3 (replacement: term_subst.substitute_corresponding_in_terms/3)

  • pred apply_substitution_in_term/3 (replacement: term_subst.apply_substitution_in_term/3)

  • pred apply_substitution_in_terms/3 (replacement: term_subst.apply_substitution_in_terms/3)

  • pred apply_rec_substitution_in_term/3 (replacement: term_subst.apply_rec_substitution_in_term/3)

  • pred apply_rec_substitution_in_terms/3 (replacement: term_subst.apply_rec_substitution_in_terms/3)

  • func term_list_to_var_list/2 (replacement: term_subst.term_list_to_var_list/1)

  • pred term_list_to_var_list/2 (replacement: term_subst.term_list_to_var_list/2)

  • func var_list_to_term_list/2 (replacement: term_subst.var_list_to_term_list/1)

  • pred var_list_to_term_list/2 (replacement: term_subst.var_list_to_term_list/2)

  • pred unify_term/4 (replacement: term_unify.unify_terms/4)

  • pred unify_term_list/4 (replacement: term_unify.unify_term_lists/4)

  • pred unify_term_dont_bind/5 (replacement: term_unify.unify_terms_dont_bind/5)

  • pred unify_term_list_dont_bind/5 (replacement: term_unify.unify_term_lists_dont_bind/5)

  • pred list_subsumes/3 (replacement: term_unify.first_term_list_subsumes_second/3)

  • func vars/1 (replacement: term_vars.vars_in_term/1)

  • pred vars/2 (replacement: term_vars.vars_in_term/2)

  • func vars_2/2 (replacement: term_vars.vars_in_term_acc/3)

  • pred vars_2/3 (replacement: term_vars.vars_in_term_acc/3)

  • func vars_list/1 (replacement: term_vars.vars_in_terms/1)

  • pred vars_list/2 (replacement: term_vars.vars_in_terms/2)

  • pred contains_var/2 (replacement: term_vars.term_contains_var/2)

  • pred contains_var_list/2 (replacement: term_vars.terms_contain_var/2)

  • func context_init/2 (replacement: term_context.context_init/2)

  • pred context_init/3 (replacement: term_context.context_init/2)

  • func context_init/0 (replacement: term_context.dummy_context/0)

  • pred context_init/1 (replacement: term_context.dummy_context/0)

  • func dummy_context_init/0 (replacement: term_context.dummy_context/0)

  • pred is_dummy_context/1 (replacement: term_context.is_dummy_context/1)

  • func context_file/1 (replacement: term_context.context_file/1)

  • pred context_file/2 (replacement: term_context.context_file/1)

  • func context_line/1 (replacement: term_context.context_line/1)

  • pred context_line/2 (replacement: term_context.context_line/1)

New term_context module

• This new module defines the term_context type, and contains predicates and functions that operate on that type.

New term_int module

• This new module contains predicates that recognize terms that contain integers, and functions that construct such terms.

Changes to the term_io module

• The following predicates and functions have been added:

  • func constant_to_string/2
  • func escaped_char_to_string/2
  • func quoted_char_to_string/2
  • pred format_constant/4
  • pred format_escaped_char/4
  • pred format_escaped_string/4
  • pred format_quoted_atom/4
  • pred format_quoted_char/4
  • pred format_quoted_string/4
  • pred format_term/5
  • pred format_term_nl/5
  • pred format_term_with_op_table/6
  • pred format_term_nl_with_op_table/6
  • pred format_variable/5
  • pred format_variable_with_op_table/6
  • func term_to_string/2
  • func term_nl_to_string/2
  • func term_with_op_table_to_string/3
  • func term_nl_with_op_table_to_string/3
  • func variable_to_string/2
  • func variable_with_op_table_to_string/3
  • pred write_quoted_atom/3
  • pred write_quoted_atom/4
  • pred write_quoted_char/3
  • pred write_quoted_char/4
  • pred write_quoted_string/3
  • pred write_quoted_string/4

• The order of the arguments of the following predicates has been changed:

  • pred write_variable/4
  • pred write_variable/5
  • pred write_variable_with_op_table/4
  • pred write_variable_with_op_table/5

• The following predicates have been removed:

  • pred read_term/3 (replacement: mercury_term_parser.read_term/3)
  • pred read_term/4 (replacement: mercury_term_parser.read_term/4)
  • pred read_term_with_op_table/4 (replacement: mercury_term_parser.read_term_with_op_table/4)
  • pred read_term_with_op_table/5 (replacement: mercury_term_parser.read_term_with_op_table/5)

New term_subst module

• This new module contains predicates that perform substitutions of various kinds on terms.

New term_unify module

• This new module contains predicates that perform unifications.

New term_vars module

• This new module contains predicates and functions that find variables in terms.

Changes to the thread module

• The following predicates have been added:

  • pred spawn_native_joinable/5
  • pred join_thread/4

Changes to the tree_bitset module

• The following predicates and functions have been added:

  • func from_list/1
  • func from_sorted_list/1
  • pred nondet_member/2
  • pred remove_leq/3
  • pred remove_gt/3
  • func ucount/1

• The documentation of the following predicates and functions have been clarified:

  • func sorted_list_to_set/1
  • pred sorted_list_to_set/2

Changes to the tree234 module

• The following predicates and functions have been added:

  • pred is_non_empty/1
  • pred max_key/2
  • pred min_key/2
  • pred sorted_keys_match/2
  • func ucount/1
  • pred ucount/2

• The following function has been marked obsolete:

  • func tree234_to_doc/1 (replacement: pretty_printer.tree234_to_doc/1)

• We have added cc_multi versions of many of the higher-order predicates in this module.

Changes to the tree_bitset module

• The following predicates and functions have been added:

  • func ucount/1
  • pred ucount/2

• The following obsolete predicate has been removed:

  • pred empty/1

Changes to the type_desc module

• The following predicates have been added:

  • pred make_type/3
  • pred pseudo_type_ctor/2
  • pred pseudo_type_args/2

Changes to the uint module

• The following type has had its typeclass memberships changed:

  • The type uint is now an instance of the new uenum typeclass.

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2
  • func ubits_per_uint/0

• The following function has been marked obsolete:

  • func uint_to_doc/1 (replacement: pretty_printer.uint_to_doc/1)

Changes to the uint8 module

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2

• The following function has been marked obsolete:

  • func uint8_to_doc/1 (replacement: pretty_printer.uint8_to_doc/1)

Changes to the uint16 module

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2

• The following function has been marked obsolete:

  • func uint16_to_doc/1 (replacement: pretty_printer.uint16_to_doc/1)

Changes to the uint32 module

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2

• The following function has been marked obsolete:

  • func uint32_to_doc/1 (replacement: pretty_printer.uint32_to_doc/1)

Changes to the uint64 module

• The following functions have been added:

  • func <<u/2
  • func >>u/2
  • func unchecked_left_ushift/2
  • func unchecked_right_ushift/2

• The following function has been marked obsolete:

  • func uint64_to_doc/1 (replacement: pretty_printer.uint64_to_doc/1)

Changes to the version_array module

• The following predicates and functions have been added:

  • func uinit/2
  • func unsafe_uinit/2
  • pred lookup/3
  • func ulookup/2
  • pred ulookup/3
  • pred uset/4
  • func uelem/2
  • func uelem :=/3
  • func usize/1
  • func uresize/3
  • pred uresize/4

• The following function has been marked obsolete:

  • func version_array_to_doc/1 (replacement: pretty_printer.version_array_to_doc/1)

Changes to the version_array2d module

• The following predicates and functions have been added:

  • func uinit/3
  • pred ubounds/3
  • pred in_ubounds/3
  • pred lookup/4
  • func ulookup/3
  • pred ulookup/4
  • pred uset/5
  • func uelem/3
  • func uelem :=/4
  • func usize/1
  • func uresize/4
  • pred uresize/5

Changes to the version_bitmap module

• The following predicates have been added:

  • pred get_bit/3
  • pred set_bit/4

Changes to the version_hash_table module

• The following predicate has been added:

  • pred lookup/3

• The following obsolete predicates have been removed:

  • pred char_hash/2
  • pred float_hash/2
  • pred generic_hash/2
  • pred int_hash/2
  • pred string_hash/2
  • pred uint_hash/2

Changes to the Mercury language

• The new pragma format_call can now be used to ask the compiler to perform the same checks on calls to a named predicate or function as the compiler performs on calls to string.format, io.format and stream.string_writer.format. These checks test whether the format string matches the provided list of values.

• You can now disable another two kinds of warning with a disable_warning scope.

  First, code such as

  disable_warning [unknown_format_calls] (
      ...
  )
  

  will disable warnings about any calls in the scope to string.format, io.format and/or stream.string_writer.format for which the compiler cannot tell whether there are any mismatches between the format string and the supplied values, even if the module is compiled with --warn-unknown-format-calls.

  Second, code such as

  disable_warning [warn_repeated_singleton_vars] (
      ...
  )
  

  will disable warnings in the scope about variables whose names start with an underscore, indicating that they should be singleton variables, but which nevertheless occur more than once.

• Floating point number literals may now contain an underscore between the digits forming the fraction part and the e or E that introduces the exponent part.

• You can now use the escape sequence '\e' to refer to the ESC (escape) character, just as you can use '\n' to refer to the newline character.

Changes to the Mercury compiler

• We now enforce a (previously unstated) requirement that existentially quantified type variables and existential class constraints in a subtype definition are listed in the same order as in the supertype definition.

• We have fixed a bug where the compiler generated incorrect code in C# and Java grades when a subtype type definition did not repeat the field names of its base type.

• The compiler now ignores comments when warning about unused arguments in foreign_proc pragmas. Warnings can no longer be suppressed by mentioning a variable in a comment; use a leading underscore to mark intentionally unused variables. This change also prevents spurious warnings about return statements caused by the word return appearing only in comments.

• We have improved the typechecking and modechecking of type conversion expressions.

• We have fixed a bug where --warn-unused-imports did not warn about unused modules that are also imported by an ancestor of the current module.

• The compiler now uses colors in error messages to draw programmers' attention to the most relevant parts of diagnostics. Users can change the color scheme using the new option --color-scheme or using the new environment variable MERCURY_COLOR_SCHEME. They can also disable the use of color entirely using the new option --no-color-diagnostics or by setting the NO_COLOR environment variable. For the details, please see the new Diagnostic output chapter of the Mercury Users' guide.

• We have added a new option --warn-ambiguous-pragmas that tells the compiler to generate warnings for pragmas that specify a name/arity pair, when there is both a predicate and a function with that name and arity, and the pragma does not specify which one it is for.

• We have added a new option --warn-redundant-coerce, that tells the compiler to generate warnings for type conversions from one type to the same type. This option is enabled by default.

• We have added a new option --warn-repeated-singleton-variables, which may be shortened to --warn-repeated-singleton-vars, that tells the compiler to generate warnings for variables whose name starts with an underscore, indicating that they should be singletons, that nevertheless occur more than once. Until now, warnings about such variables were controlled by the --warn-singleton-variables option. This option is enabled by default.

• We have added the option --error-files-in-subdir to place .err files under the Mercury subdirectory when using mmc --make.

• We have raised the default value of --output-compile-error-lines to 100.

• We have added a new option --reverse-error-order that tells the compiler to output error messages for higher line numbers before error messages for lower line numbers.

• We have added a new option --show-local-call-tree that tells the compiler to output a representation of the call tree of the predicates and functions of the module as ordered by a depth-first left-to-right traversal of the bodies of the first (i.e. main) procedures of those predicates and functions. This can suggest a good order for the positions of those predicates and functions in the source code.

• We have added a new option --show-pred-movability. If a user specifies this option one or more times, each time with the name of a predicate or function as the option's argument, then the compiler will generate a report about the effect of moving the named predicates and/or functions to a new module. This report will list all the other predicates and/or functions that should be moved with them, and will warn about any unwanted coupling the move would create between the old module and the new.

• We have added a new option --warn-can-fail-function. If the user specifies this option, the compiler will generate a warning for every function whose primary mode (which means the mode in which all its arguments are input) can fail without generating a return value.

  This option is for people who prefer that all functions be total, and that functions that compute a value only in some circumstances (i.e. partial functions) be expressed as predicates instead.

• We have added a new option --warn-unsorted-import-blocks. If the user specifies this option, the compiler will generate a warning if any line contains import_module or use_module declarations for more than one module, or if a block of such declarations on consecutive lines are not sorted on module name.

  The discipline enforced by this option can standardize the appearance of the sections of Mercury modules containing these declarations, make diffs of changes to these sections easier to read, and spare programmers from having to decide on a case-by-case basis exactly where they want to add a new import_module or use_module declaration.

• We have added two new options, --warn-unneeded-initial-statevars, and --warn-unneeded-initial-statevars-lambda, which report, for clause heads and lambda expressions respectively, when an argument of the form !.SV in their argument list is never updated. In most cases, changing such arguments into non-statevars will improve the code by avoiding giving readers of the code a false expectation of an update. (An exception is when a !.SV argument is not updated in one clause, but is updated in another clause.) Both options are on by default.

• We have added two new options, --warn-unneeded-final-statevars, and --warn-unneeded-final-statevars-lambda, which report, for clause heads and lambda expressions respectively, when an argument of the form !:SV in their argument list is guaranteed to be unified with the !.SV argument in the same argument list. In the absence of constraints that require keeping the predicate signature unchanged (e.g. to allow the predicate to be passed to a higher order construct), the !:SV argument should be deleted, and if the only use of the !.SV argument was to set the value of the !:SV argument, then the !.SV argument should be deleted too. Both options are on by default.

• We have made --warn-non-contiguous-clauses the default.

• We have added a new option, --allow-non-contiguity-for, which modifies the operation of two existing options, --warn-non-contiguous-clauses and --warn-non-contiguous-foreign-procs. If either of those two options is specified, the compiler will normally generate a warning if there is a gap in the list of clauses for a given predicate. The new option allows programmers to relax this requirement selectively. An option such as --allow-non-contiguity-for p1,f2,p3 tells the compiler to allow the clauses of the named predicates and/or functions to be intermingled with each other, but not with the clauses of any other predicates or functions. This option may be given more than once.

• We have added a new option, --warn-too-private-instances, which asks the compiler to generate warnings for instances that are private to the module containing them, even though both the typeclass they are for and all the type constructors occurring in their argument vector are visible outside that module.

• We have replaced the --no-warn-only-one-format-string-error compiler option with the new option named --warn-all-format-string-errors.

• We have renamed the --generate-module-order compiler option to --also-output-module-order, and changed the extension of the file to which it writes its output: it is now .module_order.

• The deprecated option --trail-segments has been deleted, and the grade component trseg is no longer accepted as a synonym for tr.

• The new options --java-runtime-flags and --quoted-java-runtime-flag can be used to set flags for the Java interpreter in the launcher shell scripts or batch files generated by the compiler when creating executables in the java grade.

• --javac-flags is now accepted as a synonym for --java-flags. Also, --javac-flag is now accepted as a synonym for --java-flag.

• We have changed the preferred name of several options that each specify a flag to be passed to a command after quoting. The new names are the following:

  --quoted-cflag              (old name: --cflag)    
  --quoted-gcc-flag           (old name: --gcc-flag)    
  --quoted-clang-flag         (old name: --clang-flag)    
  --quoted-msvc-flag          (old name: --msvc-flag)    
  --quoted-javac-flag         (old name: --javac-flag)    
  --quoted-java-flag          (old name: --java-flag)    
  --quoted-java-runtime-flag  (old name: --java-runtime-flag)    
  --quoted-csharp-flag        (old name: --csharp-flag)    
  --quoted-ld-flag            (old name: --ld-flag)    
  --quoted-ld-libflag         (old name: --ld-libflag)    
  

  The compiler still accepts the old names, but we intend to remove them after the next stable release.

• We have changed the preferred name of the --warn-interface-imports option to --warn-unused-interface-imports, which is more descriptive.

  The compiler still accepts the old name, but we intend to remove it after the next stable release.

• On macOS systems, the configure script now uses the value of the MACOSX_DEPLOYMENT_TARGET environment variable as the default value for the deployment target, if set.

• The --no-ansi-c option has been deprecated and will be removed in a future release. The option has not had any effect for a long time.

• We have deleted the --java-object-file-extension option, which has only ever had one useful value, which is the default value, ".class".

• We have deleted the --generate-bytecode option, which has never been useful, because the bytecode interpreter it generated code for was never complete enough to be usable.

• The --install-command-dir-option option has been deprecated and will be removed in a future release. This option has not had any effect for a long time.

• We have added more options to selectively turn off warnings that were previously not under such control. These options are the following.

  --no-warn-cannot-table
  --no-warn-disj-fills-partial-inst
  --no-warn-duplicate-abstract-instances
  --no-warn-exported-insts-for-private-type
  --no-warn-missing-descendant-modules
  --no-warn-missing-state-var-init
  --no-warn-moved-trace-goal
  --no-warn-no-auto-parallelisation
  --no-warn-no-recursion
  --no-warn-nonexported-pragma
  --no-warn-requested-by-code
  --no-warn-requested-by-option
  --no-warn-subtype-ctor-order
  --no-warn-typecheck-ambiguity-limit
  --no-warn-unknown-warning-name
  --no-warn-unneeded-purity-indicator
  --no-warn-unneeded-purity-pragma
  --no-warn-unneeded-purity-pred-decl
  

• We have renamed three existing options:

  --inform-ite-instead-of-switch       to --warn-ite-instead-of-switch
  --inform-incomplete-switch           to --warn-incomplete-switch
  --inform-incomplete-switch-threshold to --warn-incomplete-switch-threshold
  

  These options will still be available under their old names at least until the next release.

• We have added the new option --no-warn-redundant-code, which tells the compiler not to generate warnings about redundant elements in Mercury code, such as duplicate imports of the same module. These warnings were previously controlled by the --no-warn-simple-code option.

Changes to the Mercury debugger

• The dump command has a new option: dump -p Var will dump the value of the given variable in a prettyprinted form.

• The dump command can now also dump only the selected part of a given variable.

• The stack command now identifies cliques by drawing boxes next to them on the left hand side of the screen.

Changes to the Mercury deep profiler

• Programs that have been compiled in a deep profiling grade will now, by default, put profiling data in files whose names contain both the name of the program being profiled, and the date and time of the profiling run. The file names will have the form <prog>_on_<date>_at_<time>.data and <prog>_on_<date>_at_<time>.procrep.

  To get the old behaviour, pass the runtime option --deep-std-name via the MERCURY_OPTIONS environment variable. This will put the profiling data in files named Deep.data and Deep.procrep.

Changes to the Mercury implementation

• We have upgraded the bundled Boehm GC to v8.2.8 and libatomic_ops to v7.8.2.

Portability improvements

• We now support using the 64-bit (i.e. x64) version of Microsoft Visual C++ as a C compiler with Mercury. See README.MS-VisualC.md for further details.

• We have updated the script tools/configure_cross to support cross-compiling using clang.

Changes to the extras distribution

• We have deleted the old_term_parser library.

Other changes

• We have added a new option, --with-pkgversion, to the configure script. This option lets you specify an identifying string that will be included in the version information displayed by programs in the Mercury system.

For news about earlier versions, see the Documentation/NEWS_* files.