go-toml/parser/syn_key.go

64 lines
2.0 KiB
Go

package parser
import "github.com/mmakaay/toml/parsekit"
// The primary building block of a TOML document is the key/value pair.
func stateKeyValuePair(p *parsekit.P) parsekit.StateFn {
switch {
case p.SkipConsecutive(whitespace + carriageReturn + newline):
return stateKeyValuePair
case p.Upcoming(hash):
return p.ToChildState(stateCommentStart)
case p.Upcoming(startOfKey):
return stateKey
default:
return stateEndOfFile
}
}
// A key may be either bare, quoted or dotted.
func stateKey(p *parsekit.P) parsekit.StateFn {
if p.AcceptMatching(bareKeyChars) {
return statebareKeyChars
}
return p.UnexpectedInput("a valid key name")
}
// Bare keys may only contain ASCII letters, ASCII digits,
// underscores, and dashes (A-Za-z0-9_-). Note that bare
// keys are allowed to be composed of only ASCII digits,
// e.g. 1234, but are always interpreted as strings.
func statebareKeyChars(p *parsekit.P) parsekit.StateFn {
p.AcceptConsecutive(bareKeyChars)
p.EmitLiteral(ItemKey)
return stateEndOfKeyOrKeyDot
}
// Dotted keys are a sequence of bare or quoted keys joined with a dot.
// This allows for grouping similar properties together:
func stateEndOfKeyOrKeyDot(p *parsekit.P) parsekit.StateFn {
// Whitespace around dot-separated parts is ignored, however,
// best practice is to not use any extraneous whitespace.
p.SkipConsecutive(whitespace)
if p.SkipMatching(dot) {
p.Emit(ItemKeyDot, "")
p.SkipConsecutive(whitespace)
return stateKey
}
return stateKeyAssignment
}
// Keys are on the left of the equals sign and values are on the right.
// Whitespace is ignored around key names and values. The key, equals
// sign, and value must be on the same line (though some values can
// be broken over multiple lines).
func stateKeyAssignment(p *parsekit.P) parsekit.StateFn {
p.SkipConsecutive(whitespace)
if p.SkipMatching(equal) {
p.Emit(ItemAssignment, "")
p.SkipConsecutive(whitespace)
return stateValue
}
return p.UnexpectedInput("a value assignment")
}