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100 lines
2.8 KiB
JavaScript

'use strict';
const pad = require("pad");
const chalk = Object.assign(require("chalk"), {enabled: true});
const defaultValue = require("default-value");
module.exports = function createBetterPegTracer(parsedString) {
let currentLevel = 0;
let lastWasFail = false
let parsedStringLines = parsedString.split("\n");
let lastSeenRule = [];
return {
trace: function trace(event) {
if (event.type === "rule.fail" || event.type === "rule.match") {
currentLevel -= 1;
}
let ruleIndent = pad("", currentLevel * 4);
let eventName = event.type.replace(/^rule\./, "");
let isMultiline = (parsedStringLines.length > 1);
let startLine = event.location.start.line;
let endLine = event.location.end.line;
let startColumn = event.location.start.column;
let endColumn = event.location.end.column;
let firstLine = parsedStringLines[startLine - 1];
let lastLine = parsedStringLines[endLine - 1];
let affectedString, color, startPosition, endPosition, position;
if (isMultiline) {
startPosition = `${pad(4, startLine)}:${pad(2, startColumn)}`;
if (startLine !== endLine || startColumn !== endColumn) {
endPosition = `${pad(4, endLine)}:${pad(2, endColumn)}`;
}
} else {
startPosition = startColumn;
if (startColumn !== endColumn) {
endPosition = endColumn;
}
}
position = `${pad(8, startPosition)} ${chalk.white("│")} ${pad(8, defaultValue(endPosition, ""))}`;
if (startLine === endLine) {
if (startColumn === endColumn) {
/* Not reading a range, but rather attempting to find a match from the current point. */
if (event.location.start.offset < parsedString.length) {
affectedString = chalk.gray(`${firstLine.slice(startColumn - 1)} ...`);
} else {
affectedString = "";
}
} else {
affectedString = firstLine.slice(startColumn - 1, endColumn - 1);
}
} else {
affectedString = `${firstLine.slice(startColumn - 1)} ... ${lastLine.slice(0, endColumn - 1)}`;
}
if (event.type === "rule.enter") {
lastSeenRule[currentLevel] = event.rule;
}
if (event.type === "rule.match") {
color = chalk.green;
} else if (event.type === "rule.fail") {
color = chalk.red;
} else {
color = chalk.white;
}
let crumbs = lastSeenRule.slice(0, currentLevel).concat([color(event.rule)]);
let limitedCrumbs;
if (crumbs.length > 6) {
limitedCrumbs = crumbs.slice(0, 2).concat([`... ${crumbs.length - 5} hidden ...`]).concat(crumbs.slice(-3));
} else {
limitedCrumbs = crumbs;
}
let line = [
position,
pad(eventName, 5),
chalk.gray(pad(limitedCrumbs.join(" -> "), "90")),
affectedString
].join(` ${chalk.white("│")} `);
process.stdout.write(color(line + "\n"));
if (event.type === "rule.enter") {
currentLevel += 1;
}
}
}
}