83 lines
2.9 KiB
Go
83 lines
2.9 KiB
Go
package parser
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import "git.makaay.nl/mauricem/go-parsekit"
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var (
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// There are four ways to express strings: basic, multi-line basic,
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// literal, and multi-line literal. All strings must contain only valid
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// UTF-8 characters. * Multi-line basic strings are surrounded by three
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// quotation marks on each side. * Basic strings are surrounded by
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// quotation marks.
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doubleQuote3 = c.String(`"""`)
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// Any Unicode character may be used except those that must be escaped:
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// quotation mark, backslash, and the control characters (U+0000 to
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// U+001F, U+007F).
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charThatMustBeEscaped = c.AnyOf(c.RuneRange('\u0000', '\u001F'), c.Rune('\u007F'))
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// For convenience, some popular characters have a compact escape sequence.
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//
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// \b - backspace (U+0008)
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// \t - tab (U+0009)
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// \n - LF (U+000A)
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// \f - form feed (U+000C)
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// \r - carriage return (U+000D)
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// \" - quote (U+0022)
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// \\ - backslash (U+005C)
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// \uXXXX - unicode (U+XXXX)
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// \UXXXXXXXX - unicode (U+XXXXXXXX)
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validEscapeChar = c.AnyOf(c.Runes('b', 't', 'n', 'f', 'r'), a.DoubleQuote, a.Backslash)
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shortEscape = c.Sequence(a.Backslash, validEscapeChar)
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shortUTF8Escape = c.Sequence(a.Backslash, c.Rune('u'), c.Repeat(4, a.HexDigit))
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longUTF8Escape = c.Sequence(a.Backslash, c.Rune('U'), c.Repeat(8, a.HexDigit))
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validEscape = c.AnyOf(shortEscape, shortUTF8Escape, longUTF8Escape)
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)
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func startString(p *parsekit.P) {
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p.Expects("a string value")
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switch {
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case p.On(doubleQuote3).RouteTo(startMultiLineBasicString).End():
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case p.On(a.DoubleQuote).RouteTo(startBasicString).End():
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}
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}
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func startBasicString(p *parsekit.P) {
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p.Expects("a basic string")
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p.On(a.DoubleQuote).Skip().RouteTo(parseBasicString).ThenTo(basicStringSpecifics)
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}
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func parseBasicString(p *parsekit.P) {
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p.Expects("string contents")
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switch {
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case p.On(charThatMustBeEscaped).End():
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p.EmitError("invalid character in basic string: %q (must be escaped)", p.LastMatch)
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case p.On(validEscape).Accept().RouteRepeat().End():
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case p.On(a.Backslash).RouteReturn().End():
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case p.On(a.DoubleQuote).RouteReturn().End():
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case p.On(a.AnyRune).Accept().RouteRepeat().End():
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}
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}
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// Specific handling of input for basic strings.
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// * A double quote ends the string
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// * No additional \escape sequences are allowed. What the spec say about this:
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// "All other escape sequences [..] are reserved and, if used, TOML should
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// produce an error.""
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func basicStringSpecifics(p *parsekit.P) {
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p.Expects("string contents")
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switch {
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case p.On(a.DoubleQuote).Skip().End():
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p.EmitInterpreted(ItemString)
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p.RouteTo(startKeyValuePair)
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case p.On(a.Backslash).End():
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p.EmitError("invalid escape sequence")
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}
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}
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func startMultiLineBasicString(p *parsekit.P) {
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p.Expects("a multi-line basic string")
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if p.On(doubleQuote3).Skip().End() {
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p.EmitError("not yet implemented")
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}
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}
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