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Allow starting a number with a decimal point #296

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merged 1 commit into from
May 18, 2022
Merged

Allow starting a number with a decimal point #296

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13 changes: 8 additions & 5 deletions src/Insect/Parser.purs
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Original file line number Diff line number Diff line change
Expand Up @@ -89,10 +89,10 @@ whiteSpace = token.whiteSpace
-- | Parse a number.
number ∷ P Decimal
number = do
intPart ← digits

mFracPart ← optionMaybe (append <$> string "." <*> digits)
let fracPart = fromMaybe "" mFracPart
decimalPart ← fractionalPart <|> do
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@triallax triallax May 13, 2022 •
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Suggestions on how to better implement this are welcome.

intPart ← digits
mFracPart ← optionMaybe fractionalPart
pure (intPart <> fromMaybe "" mFracPart)

mExpPart ← optionMaybe $ try do
_ ← string "e"
Expand All @@ -103,7 +103,7 @@ number = do

whiteSpace

let floatStr = intPart <> fracPart <> expPart
let floatStr = decimalPart <> expPart

case fromString floatStr of
Just num →
Expand All @@ -118,6 +118,9 @@ number = do
ds ← some $ oneOf ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'] <?> "a digit"
pure $ fromCharArray (fromFoldable ds)

fractionalPart ∷ P String
fractionalPart = (<>) <$> string "." <*> digits

fromCharArray = fromCodePointArray <<< map codePointFromChar

signAndDigits ∷ P String
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19 changes: 18 additions & 1 deletion test/Main.purs
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Expand Up @@ -110,11 +110,28 @@ main = runTest do
, "+3.50"
]

allParseAs (Expression (scalar 0.2))
[ "0.2"
, " 0.2 "
, "+0.2 "
, ".2"
, "+.2"
]

allParseAs (Expression (Negate (scalar 0.61)))
[ "-0.61"
, "-.61"
, "- .61"
]

shouldParseAs (Expression (scalar 0.05)) ".05"

shouldFail "123.."
shouldFail "0.."
shouldFail ".0."
shouldFail "."
shouldFail ".2"
shouldFail ". 2"
shouldFail "..2"

test "Large numbers" do
allParseAs (Expression (scalar 1234567890000000.0))
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