codehs-console
Version:
Helpers for console programs in the CodeHS editor.
511 lines (461 loc) • 16.2 kB
JavaScript
/* Console
* =====================
* A console represents a text console that allows the user to print, println,
* and read an integer using readInt, and read a float using readFloat. These
* functions pop up prompt dialogs and make sure that the results are actually
* of the desired type.
*
* @author Jeremy Keeshin July 9, 2012
*
*/
;
var safeEval = require('codehs-js-utils').safeEval;
var lines = [];
var solution = null;
var TESTER_MESSAGE = '#tester-message';
var PUBLIC_METHODS = [];
/**
* Set up an instance of the console library.
* @constructor
*/
function CodeHSConsole() {
this.internalOutput = [];
this.internalOutputBuffer = '';
}
/**
* Adds a method to the public methods array.
* @param {string} name - Name of the method.
*/
CodeHSConsole.registerPublicMethod = function(name) {
PUBLIC_METHODS.push(name);
};
/**
* Generate strings for the public methods to bring them to the
* public namespace without having to call them with the console instance.
* @returns {string} Line broken function definitions.
*/
CodeHSConsole.getNamespaceModifcationString = function() {
var result = '';
for (var i = 0; i < PUBLIC_METHODS.length; i++) {
var curMethod = PUBLIC_METHODS[i];
// Actually create a method in this scope with the name of the
// method so the student can easily access it. For example, we
// might have a method like CodeHSConsole.prototype.print, but we
// want the student to be able to access it with just `print`, but
// the proper context for this.
result +=
'function ' +
curMethod +
'(){\n' +
'\treturn __console__.' +
curMethod +
'.apply(__console__, arguments);\n' +
'}\n';
}
return result;
};
/**
* Generate stub strings for the public methods to bring them to the
* namespace without having to call them with the console instance.
* @returns {string} Line broken function definitions.
*/
CodeHSConsole.getStubString = function() {
var result = '';
_.each(PUBLIC_METHODS, function(method) {
result += 'function ' + method + '(){\n' + '\treturn 0;\n' + '}\n';
});
return result;
};
/**
* Set the solution code for a given exercise.
* @param {string} soln - Solution code.
*/
CodeHSConsole.setSolution = function(soln) {
solution = soln;
};
/**
* Check the console output for correctness against solution code.
* returns {object} Dictionary containing boolean of success and message.
*/
CodeHSConsole.prototype.checkOutput = function() {
if (!solution) {
return;
}
var graded = {
success: true,
message: '<strong>Nice job!</strong> You got it!',
};
if ($('#console').html().length === 0) {
graded.success = false;
graded.message = "You didn't print anything.";
} else if (lines.length != solution.length) {
graded.success = false;
graded.message =
'<strong>Not quite.</strong> Take a look at the ' +
'example output in the exercise tab.';
} else {
for (var i = 0; i < lines.length; i++) {
var line = lines[i];
var correct = solution[i];
var regex = new RegExp(correct);
if (line.search(regex) !== 0) {
graded.success = false;
graded.message =
'<strong>Not quite.</strong> Take a look ' +
'at the example output in the exercise tab.';
}
}
}
$(TESTER_MESSAGE).html(graded.message);
if (graded.success) {
$(TESTER_MESSAGE)
.removeClass('gone')
.removeClass('alert-error')
.addClass('alert-info');
} else {
$(TESTER_MESSAGE)
.removeClass('gone')
.removeClass('alert-info')
.addClass('alert-error');
}
return graded;
};
var bufferedOutputToArray = function(bufferedOutput) {
var bufferedOutputArray = bufferedOutput.split('\n');
// remove the trailing "" that happens if the final element is a \n
if (bufferedOutputArray[bufferedOutputArray.length - 1].length === 0) {
bufferedOutputArray = bufferedOutputArray.slice(0, -1);
}
return bufferedOutputArray;
};
/**
* A non-dom-mutating print for use in autograders.
*/
CodeHSConsole.prototype.quietPrint = function(string) {
if (!this.internalOutputBuffer) {
this.internalOutputBuffer = '';
}
this.internalOutputBuffer += string;
};
/**
* A non-dom-mutating println for use in autograders.
*/
CodeHSConsole.prototype.quietPrintln = function(anything) {
this.quietPrint(anything + '\n');
};
/**
* Gets the internal output.
*/
CodeHSConsole.prototype.flushQuietOutput = function() {
if (!this.internalOutputBuffer) {
this.internalOutputBuffer = '';
}
if (!this.internalOutput) {
this.internalOutput = [];
}
var output = this.internalOutput.concat(bufferedOutputToArray(this.internalOutputBuffer));
this.internalOutput = [];
this.internalOutputBuffer = '';
return output;
};
/**
* Get the output from the console.
* @returns {string}
*/
CodeHSConsole.getOutput = function() {
return $('#console').text();
};
/**
* Check if the console exists.
* Important to check before attempting to select and extract output.
*/
CodeHSConsole.exists = function() {
return $('#console').exists();
};
/**
* Clear the console's text.
*/
CodeHSConsole.clear = function() {
lines = [];
$('#console').html('');
$(TESTER_MESSAGE).addClass('gone');
};
/**
* Private method used to read a line.
* @param {string} str - The line to be read.
* @param {boolean} looping - Unsure. This is a messy method.
*/
CodeHSConsole.prototype.readLinePrivate = function(str, looping) {
if (typeof looping === 'undefined' || !looping) {
this.print(str);
}
var console = $('#console');
var lines;
var result;
if (console.length) {
$('#console').css('margin-top', '180px');
// take max 20 lines, last line is prompt string so we remove and
// add extra spacing before putting it back on
lines = _.takeRight(
$('#console')
.text()
.split('\n'),
21
);
lines.pop();
var text = lines.concat(['', '', str]).join('\n');
result = prompt(text);
$('#console').css('margin-top', '0px');
} else {
lines = this.internalOutput.slice(-10);
result = prompt(lines.join('\n'));
}
if (typeof looping === 'undefined' || !looping) {
this.println(result);
}
return result;
};
/**
* This is how you run the code, but get access to the
* state of the console library. The current instance
* becomes accessible in the code.
* @param {string} code - The code from the editor.
*/
CodeHSConsole.prototype.runCode = function(code, options) {
options = options || {};
var lineOffset = options.lineOffset || 0;
var publicMethodStrings = CodeHSConsole.getNamespaceModifcationString();
// This code will create a local (to the student's program) `console`
// variable, so console.log will be an alias to `println` so student code
// can act more like "real" javascript
var consoleOverride = ';var console = {}; console.log = println;\n';
// To prevent issues with the native `Set`, we swap it out here.
var setOverride = ';var __nativeSet=window.Set;var Set=window.chsSet;';
var setRestore = ';window.Set=__nativeSet;';
var wrap = '';
wrap += publicMethodStrings;
wrap += consoleOverride;
wrap += setOverride;
if (!options.overrideInfiniteLoops) {
// tool all while loops
var whileLoopRegEx = /while\s*\((.*)\)\s*{/gm;
var forLoopRegEx = /for\s*\((.*)\)\s*{/gm;
var doWhileRegEx = /do\s*\{/gm;
// Inject into while loops
code = code.replace(whileLoopRegEx, function(match, p1, offset, string) {
var lineNumber = string.slice(0, offset).split('\n').length - lineOffset;
var c =
"if(___nloops++>15000){var e = new Error('Your while loop on line " +
lineNumber +
" may contain an infinite loop. Exiting.'); e.name = 'InfiniteLoop'; e.lineNumber = " +
lineNumber +
'; throw e;}';
return 'var ___nloops=0;while(' + p1 + ') {' + c;
});
// Inject into while loops
// See comment above for while loops.
code = code.replace(forLoopRegEx, function(match, p1, offset, string) {
var lineNumber = string.slice(0, offset).split('\n').length - lineOffset;
var c =
"if(___nloops++>15000){var e = new Error('Your for loop on line " +
lineNumber +
" may contain an infinite loop. Exiting.'); e.name = 'InfiniteLoop'; e.lineNumber = " +
lineNumber +
'; throw e;}';
return 'var ___nloops=0;for(' + p1 + '){' + c;
});
// Inject into do-while loops
code = code.replace(doWhileRegEx, function(match, offset, string) {
var lineNumber = string.slice(0, offset).split('\n').length - lineOffset;
var c =
"if(___nloops++>15000){var e = new Error('Your do-while loop on line " +
lineNumber +
" may contain an infinite loop. Exiting.'); e.name = 'InfiniteLoop'; e.lineNumber = " +
lineNumber +
'; throw e;}';
return 'var ___nloops=0;do {' + c;
});
}
wrap += code;
wrap += "\n\nif(typeof start == 'function') {start();} ";
wrap += setRestore;
wrap += '__console__.checkOutput();';
this.internalOutput = [];
return safeEval(wrap, this, '__console__');
};
/**
* Method to test whether the code is requesting user input at all.
* @param {string} code - The code from the editor
*/
CodeHSConsole.prototype.hasUserinput = function(code) {
return code.match(new RegExp('readLine|readInt|readFloat|readBoolean|readNumber'));
};
/** ************* PUBLIC METHODS *******************/
/**
* Clear the console.
*/
CodeHSConsole.prototype.clear = function() {
if (arguments.length !== 0) {
throw new Error('You should not pass any arguments to clear');
}
CodeHSConsole.clear();
};
CodeHSConsole.registerPublicMethod('clear');
/**
* Print a line to the console.
* @param {string} ln - The string to print.
*/
CodeHSConsole.prototype.print = function(ln) {
if (arguments.length !== 1) {
throw new Error('You should pass exactly 1 argument to print');
}
var console = $('#console');
if (console.length) {
console.html($('#console').html() + ln);
console.scrollTop($('#console')[0].scrollHeight);
lines = console.html().split('\n');
lines.splice(lines.length - 1, 1);
} else {
// we must be running outside of the site.
// if there's a print attached to the console, use that, otherwise log like normal.
this.internalOutput.push(ln);
typeof window.console.print === 'function'
? window.console.print(ln)
: window.console.log(ln);
}
};
CodeHSConsole.registerPublicMethod('print');
/**
* Print a line to the console.
* @param {string} ln - The string to print.
*/
CodeHSConsole.prototype.println = function(ln) {
if (arguments.length === 0) {
ln = '';
} else if (arguments.length !== 1) {
throw new Error('You should pass exactly 1 argument to println');
} else {
this.print(ln + '\n');
$('#console').scrollTop();
}
};
CodeHSConsole.registerPublicMethod('println');
/* Read a number from the user using JavaScripts prompt function.
* We make sure here to check a few things.
*
* 1. If the user checks "Prevent this page from creating additional dialogs," we handle
* that gracefully, by checking for a loop, and then returning a DEFAULT value.
* 2. That we can properly parse a number according to the parse function PARSEFN passed in
* as a parameter. For floats it is just parseFloat, but for ints it is our special parseInt
* which actually does not even allow floats, even they they can properly be parsed as ints.
* 3. The errorMsgType is a string helping us figure out what to print if it is not of the right
* type.
*/
CodeHSConsole.prototype.readNumber = function(str, parseFn, errorMsgType) {
var DEFAULT = 0; // If we get into an infinite loop, return DEFAULT.
var INFINITE_LOOP_CHECK = 100;
var prompt = str;
var looping = false;
var loopCount = 0;
// eslint-disable-next-line no-constant-condition
while (true) {
var result = this.readLinePrivate(prompt, looping);
if (result === null) {
return null;
}
result = parseFn(result);
// Then it was okay.
if (!isNaN(result)) {
return result;
}
if (result === null) {
return DEFAULT;
}
if (loopCount > INFINITE_LOOP_CHECK) {
return DEFAULT;
}
prompt = 'That was not ' + errorMsgType + '. Please try again. ' + str;
looping = true;
loopCount++;
}
};
CodeHSConsole.registerPublicMethod('readNumber');
/**
* Read a line from the user.
* @param {str} str - A message associated with the modal asking for input.
* @returns {str} The result of the readLine prompt.
*/
CodeHSConsole.prototype.readLine = function(str) {
if (arguments.length !== 1) {
throw new Error('You should pass exactly 1 argument to readLine');
}
return this.readLinePrivate(str, false);
};
CodeHSConsole.registerPublicMethod('readLine');
/**
* Read a bool from the user.
* @param {str} str - A message associated with the modal asking for input.
* @returns {str} The result of the readBoolean prompt.
*/
CodeHSConsole.prototype.readBoolean = function(str) {
if (arguments.length !== 1) {
throw new Error('You should pass exactly 1 argument to readBoolean');
}
return this.readNumber(
str,
function(x) {
if (x === null) {
return NaN;
}
x = x.toLowerCase();
if (x == 'true' || x == 'yes') {
return true;
}
if (x == 'false' || x == 'no') {
return false;
}
return NaN;
},
'a boolean (true/false)'
);
};
CodeHSConsole.registerPublicMethod('readBoolean');
/* Read an int with our special parseInt function which doesnt allow floats, even
* though they are successfully parsed as ints.
* @param {str} str - A message associated with the modal asking for input.
* @returns {str} The result of the readInt prompt.
*/
CodeHSConsole.prototype.readInt = function(str) {
if (arguments.length !== 1) {
throw new Error('You should pass exactly 1 argument to readInt');
}
return this.readNumber(
str,
function(x) {
var resultInt = parseInt(x);
var resultFloat = parseFloat(x);
// Make sure the value when parsed as both an int and a float are the same
if (resultInt == resultFloat) {
return resultInt;
}
return NaN;
},
'an integer'
);
};
CodeHSConsole.registerPublicMethod('readInt');
/* Read a float with our safe helper function.
* @param {str} str - A message associated with the modal asking for input.
* @returns {str} The result of the readFloat prompt.
*/
CodeHSConsole.prototype.readFloat = function(str) {
if (arguments.length !== 1) {
throw new Error('You should pass exactly 1 argument to readFloat');
}
return this.readNumber(str, parseFloat, 'a float');
};
CodeHSConsole.registerPublicMethod('readFloat');
module.exports = {
CodeHSConsole: CodeHSConsole,
PUBLIC_METHODS: PUBLIC_METHODS,
};