51 lines
1.1 KiB
Go
51 lines
1.1 KiB
Go
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package lexpr
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import (
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"strings"
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)
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const (
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digits = "0123456789"
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alpha = "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM"
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chars = "+-*/=<>@&|:!."
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)
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// scanNumber simplest scanner that accepts decimal int and float.
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func scanNumber(l *lex) bool {
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l.acceptWhile(digits, false)
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if l.atStart() {
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// not found any digit
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return false
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}
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l.accept(".")
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l.acceptWhile(digits, false)
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return !l.atStart()
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}
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// scanWord returns true if next input token contains alphanum sequence that not starts from digit and not contains.
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// spaces or special characters.
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func scanWord(l *lex) bool {
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if !l.accept(alpha) {
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return false
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}
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l.acceptWhile(alpha+digits, false)
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return true
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}
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func scanOps(l *lex) bool {
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return l.acceptWhile(chars, false)
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}
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// scanQuotedString returns true if next input tokens is quoted string. Can be used with any type of quotes.
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func scanQuotedString(l *lex, quote string) bool {
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start := l.pos
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if !strings.ContainsRune(quote, l.next()) {
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l.pos = start
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return false
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}
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if l.acceptWhileNot(quote, true) {
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l.next()
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}
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return !l.atStart()
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}
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