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The string representation of float special values is currently dependent on the target language and, for C grades, the underlying platform. As a result, values like NaN and Infinity are being printed or converted into strings in variety of ways. (See, for example bug #348 in Mantis.) This diff changes float->string conversion to detect float special values and use a consistent string representation for them. library/string.m: library/io.m: runtime/mercury_float.c: Check if a float is not-a-number or of infinite magnitude when converting floats into strings. If so, then use a standard representation of the value: "nan" for not-a-number values, and "infinity" / "-infinity" for values of infinite magnitude. For uppercase conversion specifiers in format strings, we output the above strings in uppercase (e.g. "NAN", "INFINITY"). library/float.m: Add is_infinite/1 and is_nan_or_infinite/1 as synonyms for is_inf/1 and is_nan_or_inf/1 respectively. Group float classification predicates into their own section. Upcoming change will add more of them. NEWS: Announce the above changes. tests/general/string_format_special_floats.m: tests/general/string_format_special_floats.exp: Modify this test to check that we actually print float special values as above. tests/hard_coded/write_float_special.exp: Conform to the above change. tests/EXPECT_FAIL_TESTS.all_grades: Do not expect the write_float_special test case to fail any more since the expected outputs should be the same on every platform.
22 lines
579 B
Plaintext
22 lines
579 B
Plaintext
Plus Infinity:
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%e: infinity
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%f: infinity
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%g: infinity
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%E: INFINITY
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%F: INFINITY
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%G: INFINITY
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Minus Infinity:
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%e: -infinity
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%f: -infinity
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%g: -infinity
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%E: -INFINITY
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%F: -INFINITY
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%G: -INFINITY
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Not a number:
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%e: nan
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%f: nan
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%g: nan
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%E: NAN
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%F: NAN
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%G: NAN
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