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JavaScript

import {tokenizer, SourceLocation, tokTypes as tt, Node, lineBreak, isNewLine} from ".."
// Registered plugins
export const pluginsLoose = {}
export class LooseParser {
constructor(input, options) {
this.toks = tokenizer(input, options)
this.options = this.toks.options
this.input = this.toks.input
this.tok = this.last = {type: tt.eof, start: 0, end: 0}
if (this.options.locations) {
let here = this.toks.curPosition()
this.tok.loc = new SourceLocation(this.toks, here, here)
}
this.ahead = []; // Tokens ahead
this.context = []; // Indentation contexted
this.curIndent = 0
this.curLineStart = 0
this.nextLineStart = this.lineEnd(this.curLineStart) + 1
// Load plugins
this.options.pluginsLoose = options.pluginsLoose || {}
this.loadPlugins(this.options.pluginsLoose)
}
startNode() {
return new Node(this.toks, this.tok.start, this.options.locations ? this.tok.loc.start : null)
}
storeCurrentPos() {
return this.options.locations ? [this.tok.start, this.tok.loc.start] : this.tok.start
}
startNodeAt(pos) {
if (this.options.locations) {
return new Node(this.toks, pos[0], pos[1])
} else {
return new Node(this.toks, pos)
}
}
finishNode(node, type) {
node.type = type
node.end = this.last.end
if (this.options.locations)
node.loc.end = this.last.loc.end
if (this.options.ranges)
node.range[1] = this.last.end
return node
}
dummyNode(type) {
let dummy = this.startNode()
dummy.type = type
dummy.end = dummy.start
if (this.options.locations)
dummy.loc.end = dummy.loc.start
if (this.options.ranges)
dummy.range[1] = dummy.start
this.last = {type: tt.name, start: dummy.start, end: dummy.start, loc: dummy.loc}
return dummy
}
dummyIdent() {
let dummy = this.dummyNode("Identifier")
dummy.name = "✖"
return dummy
}
dummyString() {
let dummy = this.dummyNode("Literal")
dummy.value = dummy.raw = "✖"
return dummy
}
eat(type) {
if (this.tok.type === type) {
this.next()
return true
} else {
return false
}
}
isContextual(name) {
return this.tok.type === tt.name && this.tok.value === name
}
eatContextual(name) {
return this.tok.value === name && this.eat(tt.name)
}
canInsertSemicolon() {
return this.tok.type === tt.eof || this.tok.type === tt.braceR ||
lineBreak.test(this.input.slice(this.last.end, this.tok.start))
}
semicolon() {
return this.eat(tt.semi)
}
expect(type) {
if (this.eat(type)) return true
for (let i = 1; i <= 2; i++) {
if (this.lookAhead(i).type == type) {
for (let j = 0; j < i; j++) this.next()
return true
}
}
}
pushCx() {
this.context.push(this.curIndent)
}
popCx() {
this.curIndent = this.context.pop()
}
lineEnd(pos) {
while (pos < this.input.length && !isNewLine(this.input.charCodeAt(pos))) ++pos
return pos
}
indentationAfter(pos) {
for (let count = 0;; ++pos) {
let ch = this.input.charCodeAt(pos)
if (ch === 32) ++count
else if (ch === 9) count += this.options.tabSize
else return count
}
}
closes(closeTok, indent, line, blockHeuristic) {
if (this.tok.type === closeTok || this.tok.type === tt.eof) return true
return line != this.curLineStart && this.curIndent < indent && this.tokenStartsLine() &&
(!blockHeuristic || this.nextLineStart >= this.input.length ||
this.indentationAfter(this.nextLineStart) < indent)
}
tokenStartsLine() {
for (let p = this.tok.start - 1; p >= this.curLineStart; --p) {
let ch = this.input.charCodeAt(p)
if (ch !== 9 && ch !== 32) return false
}
return true
}
extend(name, f) {
this[name] = f(this[name])
}
loadPlugins(pluginConfigs) {
for (let name in pluginConfigs) {
let plugin = pluginsLoose[name]
if (!plugin) throw new Error("Plugin '" + name + "' not found")
plugin(this, pluginConfigs[name])
}
}
}