85 lines
3.2 KiB
Go
85 lines
3.2 KiB
Go
package parser
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import "github.com/mmakaay/toml/parsekit"
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// There are four ways to express strings: basic, multi-line basic, literal,
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// and multi-line literal. All strings must contain only valid UTF-8 characters.
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// * Multi-line basic strings are surrounded by three quotation marks on each side.
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// * Basic strings are surrounded by quotation marks.
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func stateStringValue(p *parsekit.P) parsekit.StateFn {
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switch {
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case p.SkipMatching(doubleQuote3...):
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return stateMultiLineBasicString
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case p.SkipMatching(doubleQuote):
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return p.QueueStates(stateParseString, stateBasicStringSpecific)
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}
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return p.UnexpectedInput("a string value")
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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 stateBasicStringSpecific(p *parsekit.P) parsekit.StateFn {
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switch {
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case p.SkipMatching(doubleQuote):
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if err := p.EmitInterpreted(ItemString); err != nil {
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return p.EmitError("Invalid data in string: %s", err)
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}
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return stateKeyValuePair
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case p.Upcoming(backslash):
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return p.EmitError("Invalid escape sequence")
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default:
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return p.QueueStates(stateParseString, stateBasicStringSpecific)
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}
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}
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func stateMultiLineBasicString(p *parsekit.P) parsekit.StateFn {
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p.EmitError("Not yet implemented")
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return nil
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}
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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 U+001F, U+007F).
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const invalidBasicStringCharacters string = "\"\\" +
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"\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007" +
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"\u0008\u0009\u000A\u000B\u000C\u000D\u000E\u000F" +
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"\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017" +
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"\u0018\u0019\u001A\u001B\u001C\u001D\u001E\u001F" +
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"\u007F"
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func stateParseString(p *parsekit.P) parsekit.StateFn {
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switch {
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case p.AtEndOfFile():
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return p.UnexpectedEndOfFile("basic string token")
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case p.AcceptMatching(backslash, escapeChars):
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// For convenience, some popular characters have a compact escape sequence.
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// \b - backspace (U+0008)
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// \t - tab (U+0009)
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// \n - linefeed (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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case p.AcceptMatching(shortUtf8Match...):
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// \uXXXX - unicode (U+XXXX)
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case p.AcceptMatching(longUtf8Match...):
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// \UXXXXXXXX - unicode (U+XXXXXXXX)
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case p.Upcoming(backslash) || p.Upcoming(doubleQuote):
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// Returning to the parent state to have special cases handled,
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// because there are differences between single and multi line strings.
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return p.ToParentState()
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case p.Upcoming(invalidBasicStringCharacters):
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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 U+001F, U+007F).
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r, _, _ := p.Match(invalidBasicStringCharacters)
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p.EmitError("Invalid character in basic string: %q (must be escaped)", r[0])
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return nil
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default:
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p.AcceptAny()
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}
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return stateParseString
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}
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