Alexander Medvednikov
3b6e3cb913
* json2: use Go-compatible float notation * json2: preserve JS float formatting APIs
75 lines
2.1 KiB
V
75 lines
2.1 KiB
V
module json2
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import math
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type FormatFloatAlias = f64
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struct FormatFloatHolder {
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value f64
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}
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fn assert_float_encoding[T](value T, expected string) {
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assert encode(value) == expected
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assert encode(Any(value)) == expected
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mut output := 'prefix:'.bytes()
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encode_append(value, mut output)
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assert output.bytestr() == 'prefix:' + expected
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}
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fn test_float_notation_cutoffs() {
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for value, expected in {
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f64(0): '0'
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1e-7: '1e-7'
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1e-6: '0.000001'
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1e-5: '0.00001'
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1e-4: '0.0001'
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1e6: '1000000'
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1.234567890123456e10: '12345678901.23456'
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1e20: '100000000000000000000'
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1e21: '1e+21'
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1e100: '1e+100'
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1e-100: '1e-100'
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} {
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assert_float_encoding(value, expected)
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if value != 0 {
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assert_float_encoding(-value, '-' + expected)
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}
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}
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assert encode(FormatFloatAlias(1e20)) == '100000000000000000000'
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assert encode(FormatFloatHolder{1e6}) == '{"value":1000000}'
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assert encode([f64(1e-6), 1e-7, 1e20, 1e21]) == '[0.000001,1e-7,100000000000000000000,1e+21]'
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}
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fn test_f32_notation_cutoffs() {
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for value, expected in {
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f32(0): '0'
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f32(1e-7): '1e-7'
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f32(1e-6): '0.000001'
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f32(1e6): '1000000'
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f32(1e20): '100000000000000000000'
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f32(1e21): '1e+21'
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} {
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assert_float_encoding(value, expected)
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if value != 0 {
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assert_float_encoding(-value, '-' + expected)
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}
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}
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}
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fn test_float_notation_preserves_round_trip_and_special_values() {
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for value in [math.nextafter(1e-6, 0), 1e-6, math.nextafter(1e-6, 1), math.nextafter(1e21, 0),
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1e21, math.nextafter(1e21, math.inf(1)), math.f64_from_bits(1),
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math.f64_from_bits(0x7fefffffffffffff)] {
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text := encode(value)
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assert math.f64_bits(decode[f64](text)!) == math.f64_bits(value)
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}
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assert encode(math.f64_from_bits(0x8000000000000000)) == '-0'
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assert encode(math.f32_from_bits(0x80000000)) == '-0'
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assert encode(math.nan()) == 'null'
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assert encode(math.inf(1)) == 'null'
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assert encode(math.inf(-1)) == 'null'
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// JSON formatting does not change ordinary float display.
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assert f64(1e6).str() == '1e+06'
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assert f32(1e-7).str() == '1e-07'
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}
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