chapter9.js

// Fill in the regular expressions

verify(/cat|car/,
       ["my car", "bad cats"],
       ["camper", "high art"]);

verify(/pop|prop/,
       ["pop culture", "mad props"],
       ["plop", "prrrop"]);

verify(/ferr(et|y|ari)/,
       ["ferret", "ferry", "ferrari"],
       ["ferrum", "transfer A"]);

verify(/ious\b/,
       ["how delicious", "spacious room"],
       ["ruinous", "consciousness"]);

verify(/\s(\.|,|:|;)/,
       ["bad punctuation .", "bad punctuation ,", "bad punctuation :", "bad punctuation ;"],
       ["escape the period", "bad punctuation !"]);

verify(/\w{7}/,
       ["hottentottententen"],
       ["no", "hotten totten tenten"]);

verify(/\b[^\We]+\b/i,
       ["red platypus", "wobbling nest"],
       ["earth bed", "learning ape", "BEET"]);


function verify(regexp, yes, no) {
  // Ignore unfinished exercises
  if (regexp.source == "...") return;
  for (let str of yes) if (!regexp.test(str)) {
    console.log(`Failure to match '${str}'`);
  }
  for (let str of no) if (regexp.test(str)) {
    console.log(`Unexpected match for '${str}'`);
  }
}

let text = "'I'm the cook,' he said, 'it's my job.'";
// Change this call.
console.log(text.replace(/(\W)'|'(\W)|^'/g, "$1\"$2"));
// → "I'm the cook," he said, "it's my job."


// Fill in this regular expression.
let number = /^[+\-]?(\d+(\.\d*)?|\.\d+)([eE][+\-]?\d+)?$/;

// Tests:
for (let str of ["1", "-1", "+15", "1.55", ".5", "5.",
                 "1.3e2", "1E-4", "1e+12"]) {
  if (!number.test(str)) {
    console.log(`Failed to match '${str}'`);
  }
}
for (let str of ["1a", "+-1", "1.2.3", "1+1", "1e4.5",
                 ".5.", "1f5", "."]) {
  if (number.test(str)) {
    console.log(`Incorrectly accepted '${str}'`);
  }
}