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package goparsify
import (
"bytes"
"strings"
)
// Seq matches all of the given parsers in order and returns their result as .Child[n]
func Seq(parsers ...Parserish) Parser {
parserfied := ParsifyAll(parsers...)
return NewParser("Seq()", func(ps *State, node *Result) {
node.Child = make([]Result, len(parserfied))
startpos := ps.Pos
for i, parser := range parserfied {
node.Child[i].Input = node.Input
parser(ps, &node.Child[i])
if ps.Errored() {
ps.Pos = startpos
return
}
}
node.Start = startpos
node.End = ps.Pos
})
}
// NoAutoWS disables automatically ignoring whitespace between tokens for all parsers underneath
func NoAutoWS(parser Parserish) Parser {
parserfied := Parsify(parser)
return func(ps *State, node *Result) {
oldWS := ps.WS
ps.WS = NoWhitespace
startpos := ps.Pos
parserfied(ps, node)
node.Start = startpos
node.End = ps.Pos
ps.WS = oldWS
}
}
// Any matches the first successful parser and returns its result
func Any(parsers ...Parserish) Parser {
parserfied := ParsifyAll(parsers...)
return NewParser("Any()", func(ps *State, node *Result) {
ps.WS(ps)
if ps.Pos >= len(ps.Input) {
ps.ErrorHere("!EOF")
return
}
startpos := ps.Pos
var longestError Error
expected := []string{}
for _, parser := range parserfied {
parser(ps, node)
if ps.Errored() {
if ps.Error.pos >= longestError.pos {
longestError = ps.Error
expected = append(expected, ps.Error.expected)
}
if ps.Cut > startpos {
break
}
ps.Recover()
continue
}
node.Start = startpos
node.End = ps.Pos
return
}
ps.Error = Error{
pos: longestError.pos,
expected: strings.Join(expected, " or "),
}
ps.Pos = startpos
})
}
// Some matches zero or more parsers and returns the value as .Child[n]
// an optional separator can be provided and that value will be consumed
// but not returned. Only one separator can be provided.
func Some(parser Parserish, separator ...Parserish) Parser {
return NewParser("Some()", manyImpl(0, parser, separator...))
}
// Many matches one or more parsers and returns the value as .Child[n]
// an optional separator can be provided and that value will be consumed
// but not returned. Only one separator can be provided.
func Many(parser Parserish, separator ...Parserish) Parser {
return NewParser("Many()", manyImpl(1, parser, separator...))
}
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 *Result) {
node.Child = make([]Result, 0, 5)
startpos := ps.Pos
for {
node.Child = append(node.Child, Result{Input: node.Input})
opParser(ps, &node.Child[len(node.Child)-1])
if ps.Errored() {
if len(node.Child)-1 < min || ps.Cut > ps.Pos {
ps.Pos = startpos
return
}
ps.Recover()
node.Child = node.Child[0 : len(node.Child)-1]
return
}
if sepParser != nil {
sepParser(ps, TrashResult)
if ps.Errored() {
ps.Recover()
return
}
}
}
node.Start = startpos
node.End = ps.Pos
}
}
// Maybe will 0 or 1 of the parser
func Maybe(parser Parserish) Parser {
parserfied := Parsify(parser)
return NewParser("Maybe()", func(ps *State, node *Result) {
startpos := ps.Pos
parserfied(ps, node)
if ps.Errored() && ps.Cut <= startpos {
ps.Recover()
}
node.Start = startpos
node.End = ps.Pos
})
}
// Bind will set the node .Result when the given parser matches
// This is useful for giving a value to keywords and constant literals
// like true and false. See the json parser for an example.
func Bind(parser Parserish, val interface{}) Parser {
p := Parsify(parser)
return func(ps *State, node *Result) {
startpos := ps.Pos
p(ps, node)
if ps.Errored() {
return
}
node.Result = val
node.Start = startpos
node.End = ps.Pos
}
}
// Map applies the callback if the parser matches. This is used to set the Result
// based on the matched result.
func Map(parser Parserish, f func(n *Result)) Parser {
p := Parsify(parser)
return func(ps *State, node *Result) {
startpos := ps.Pos
p(ps, node)
if ps.Errored() {
return
}
node.Start = startpos
node.End = ps.Pos
f(node)
}
}
func flatten(n *Result) {
if len(n.Child) > 0 {
sbuf := &bytes.Buffer{}
for _, child := range n.Child {
flatten(&child)
sbuf.WriteString(child.Token)
}
n.Token = sbuf.String()
}
}
// Merge all child Tokens together recursively
func Merge(parser Parserish) Parser {
return Map(parser, flatten)
}
|
