diff options
Diffstat (limited to 'src/paca.mjs')
| -rw-r--r-- | src/paca.mjs | 232 |
1 files changed, 127 insertions, 105 deletions
diff --git a/src/paca.mjs b/src/paca.mjs index b30d4cd..e8ec542 100644 --- a/src/paca.mjs +++ b/src/paca.mjs @@ -12,133 +12,155 @@ const ConcatStep = { RANGE: "range", }; -const nonConcatOperators = new Set(["*", "+", "?", "|", ")"]); - -const shouldConcat = (char, next) => - next !== undefined && - char !== "(" && - char !== "|" && - char !== "{" && - !nonConcatOperators.has(next); - -const isOperator = char => - nonConcatOperators.has(char) || char == "("; - -const numFromDigits = digits => - digits.length === 0 - ? -1 - : Number(digits.join("")); +const escapingStateStep = ({ out, state, context }, char, index, next) => ({ + out: out.concat( + char, + next !== undefined ? {operator: "concat"} : [], + ), + state: ConcatStep.ACCEPTING, + context, +}); -const tokenizeRegexStep = chars => ({ out, state, context }, char, index) => { - const next = chars[index + 1]; +const rangeStateStep = ({ out, state, context }, char, index, next) => { + if (char === "}") { + if (context.where !== "to") { + return reduced({ + out, + state, + context, + error: new SyntaxError( + "missing comma in range operator", + ), + }); + } - if (state === ConcatStep.ESCAPING) { + const from = numFromDigits(context.from); + const to = numFromDigits(context.to); + if (from > to && to != -1) { + return reduced({ + out, + state, + context, + error: new Error( + `bad range values: {${from},${to}}`, + ), + }); + } return { - out: out.concat( - char, - next !== undefined ? {operator: "concat"} : [], - ), + out: out.concat({ + operator: "range", + from, + to, + }), state: ConcatStep.ACCEPTING, - context, + context: null, }; } - if (state === ConcatStep.RANGE) { - if (char === "}") { - if (context.where !== "to") { - return reduced({ - out, - state, - context, - error: new SyntaxError( - "missing comma in range operator", - ), - }); - } - - const from = numFromDigits(context.from); - const to = numFromDigits(context.to); - if (from > to && to != -1) { - return reduced({ - out, - state, - context, - error: new Error(`bad range values: {${from},${to}}`), - }); - } - return { - out: out.concat({ - operator: "range", - from, - to, - }), - state: ConcatStep.ACCEPTING, - context: null, - }; - } - - if (char === ",") { - if (context.where === "to") { - return reduced({ - out, - state, - context, - error: new SyntaxError( - "extraneuos comma in range expression", - ), - }); - } else { - return { - out, - state, - context: { - ...context, - where: "to", - }, - }; - } - } - - if (!isNumeric(char)) { + if (char === ",") { + if (context.where === "to") { return reduced({ out, state, context, error: new SyntaxError( - "bad char in range expression: " + - char, + "extraneuos comma in range expression", ), }); + } else { + return { + out, + state, + context: { + ...context, + where: "to", + }, + }; } + } - return { + if (!isNumeric(char)) { + return reduced({ out, state, - context: { - ...context, - [context.where]: context[context.where].concat(char), - }, - }; + context, + error: new SyntaxError( + "bad char in range expression: " + + char, + ), + }); } - if (char === "\\") { - return { - out, - state: ConcatStep.ESCAPING, - context, - }; + return { + out, + state, + context: { + ...context, + [context.where]: context[context.where].concat(char), + }, + }; +}; + +const STATE_FNS = { + [ConcatStep.ESCAPING]: escapingStateStep, + [ConcatStep.RANGE ]: rangeStateStep, +}; + +const TRANSITION_FNS = { + "\\": ({ out, state, context }, char, index, next) => ({ + out, + state: ConcatStep.ESCAPING, + context, + }), + "{": ({ out, state, context }, char, index, next) => ({ + out, + state: ConcatStep.RANGE, + context: { + from: [], + to: [], + where: "from", + }, + }), +}; + +const stateTransitionOperators = new Set(Object.keys(TRANSITION_FNS)); + +const nonConcatOperators = new Set(["*", "+", "?", "|", ")"]); + +const shouldConcat = (char, next) => + next !== undefined && + char !== "(" && + char !== "|" && + char !== "{" && + !nonConcatOperators.has(next); + +const isOperator = char => + nonConcatOperators.has(char) || char == "("; + +const numFromDigits = digits => + digits.length === 0 + ? -1 + : Number(digits.join("")); + +const tokenizeRegexStep = chars => ({ out, state, context }, char, index) => { + const next = chars[index + 1]; + + if (state !== ConcatStep.ACCEPTING) { + return STATE_FNS[state]( + { out, state, context }, + char, + index, + next, + ); } - if (char === "{") { - return { - out, - state: ConcatStep.RANGE, - context: { - from: [], - to: [], - where: "from", - }, - }; + if (stateTransitionOperators.has(char)) { + return TRANSITION_FNS[char]( + { out, state, context }, + char, + index, + next, + ); } const op = isOperator(char) ? { operator: char } : char; |