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Throw error if a quantifier is quantified eg. 'a**'; throw error if start of character range is greater than the end eg. '[b-a]'

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Aadhavan Srinivasan
2025-01-28 09:40:19 -05:00
parent 125590d334
commit 4547ba74f0
1 changed files with 7 additions and 0 deletions
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7
compile.go
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@@ -469,6 +469,10 @@ func shuntingYard(re string, flags ...ReFlag) ([]postfixNode, error) {
outQueue = append(outQueue, newPostfixNode(to_append)) outQueue = append(outQueue, newPostfixNode(to_append))
topStack, _ = peek(opStack) topStack, _ = peek(opStack)
} }
outQueueFinalElement, _ := peek(outQueue)
if (c == '*' && outQueueFinalElement.nodetype == KLEENE) || (c == '+' && outQueueFinalElement.nodetype == PLUS) { // You cannot apply a quantifier to a quantifier in this way
return nil, fmt.Errorf("illegal use of token '%c'", c)
}
opStack = append(opStack, c) opStack = append(opStack, c)
} }
} }
@@ -654,6 +658,9 @@ func shuntingYard(re string, flags ...ReFlag) ([]postfixNode, error) {
// We have established that they both have a length of 1 // We have established that they both have a length of 1
startRangeRune := startRangePostfixNode.contents[0] startRangeRune := startRangePostfixNode.contents[0]
endRangeRune := endRangePostfixNode.contents[0] endRangeRune := endRangePostfixNode.contents[0]
if startRangeRune > endRangeRune {
return nil, fmt.Errorf("character range syntax is [a-b], not [b-a]")
}
chars = append(chars, newPostfixCharNode(genRange(startRangeRune, endRangeRune+1)...)) chars = append(chars, newPostfixCharNode(genRange(startRangeRune, endRangeRune+1)...))
} }