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|
package goparsify
import (
"bytes"
)
var Nil = NewParser("Nil", func(ps *State) Node {
return Node{}
})
func And(parsers ...Parserish) Parser {
if len(parsers) == 0 {
return Nil
}
parserfied := ParsifyAll(parsers...)
return NewParser("And()", func(ps *State) Node {
result := Node{Children: make([]Node, len(parserfied))}
startpos := ps.Pos
for i, parser := range parserfied {
result.Children[i] = parser(ps)
if ps.Errored() {
ps.Pos = startpos
return result
}
}
return result
})
}
func NoAutoWS(parser Parserish) Parser {
parserfied := Parsify(parser)
return func(ps *State) Node {
ps.NoAutoWS = true
ret := parserfied(ps)
ps.NoAutoWS = false
return ret
}
}
func Any(parsers ...Parserish) Parser {
if len(parsers) == 0 {
return Nil
}
parserfied := ParsifyAll(parsers...)
return NewParser("Any()", func(ps *State) Node {
longestError := Error{}
startpos := ps.Pos
for _, parser := range parserfied {
node := parser(ps)
if ps.Errored() {
if ps.Error.pos > longestError.pos {
longestError = ps.Error
}
ps.ClearError()
continue
}
return node
}
ps.Error = longestError
ps.Pos = startpos
return Node{}
})
}
func Kleene(opScan Parserish, sepScan ...Parserish) Parser {
return NewParser("Kleene()", manyImpl(0, opScan, sepScan...))
}
func Many(opScan Parserish, sepScan ...Parserish) Parser {
return NewParser("Many()", manyImpl(1, opScan, sepScan...))
}
func manyImpl(min int, op Parserish, sep ...Parserish) Parser {
var opParser = Parsify(op)
var sepParser Parser
if len(sep) > 0 {
sepParser = Parsify(sep[0])
}
return func(ps *State) Node {
var result Node
startpos := ps.Pos
for {
node := opParser(ps)
if ps.Errored() {
if len(result.Children) < min {
ps.Pos = startpos
return result
}
ps.ClearError()
return result
}
result.Children = append(result.Children, node)
if sepParser != nil {
sepParser(ps)
if ps.Errored() {
ps.ClearError()
return result
}
}
}
}
}
func Maybe(parser Parserish) Parser {
parserfied := Parsify(parser)
return NewParser("Maybe()", func(ps *State) Node {
node := parserfied(ps)
if ps.Errored() {
ps.ClearError()
}
return node
})
}
func Bind(parser Parserish, val interface{}) Parser {
p := Parsify(parser)
return func(ps *State) Node {
node := p(ps)
if ps.Errored() {
return node
}
node.Result = val
return node
}
}
func Map(parser Parserish, f func(n Node) Node) Parser {
p := Parsify(parser)
return NewParser("Map()", func(ps *State) Node {
node := p(ps)
if ps.Errored() {
return node
}
return f(node)
})
}
func flatten(n Node) string {
if n.Token != "" {
return n.Token
}
if len(n.Children) > 0 {
sbuf := &bytes.Buffer{}
for _, node := range n.Children {
sbuf.WriteString(flatten(node))
}
return sbuf.String()
}
return ""
}
func Merge(parser Parserish) Parser {
return NewParser("Merge()", Map(parser, func(n Node) Node {
return Node{Token: flatten(n)}
}))
}
|
