babel/lib/6to5/generator.js
2014-11-01 23:26:48 +11:00

325 lines
7.6 KiB
JavaScript

module.exports = function (code, ast, opts) {
var gen = new CodeGenerator(code, ast, opts);
return gen.generate();
};
module.exports.CodeGenerator = CodeGenerator;
var sourceMap = require("source-map");
var assert = require("assert");
var util = require("./util");
var t = require("./types");
var _ = require("lodash");
function CodeGenerator(code, ast, opts) {
opts = opts || {}
this.tabWidth = 2;
this.code = code;
this.opts = opts;
this.ast = ast;
this.buf = "";
this.line = 1;
this.column = 0;
this._indent = 0;
if (opts.sourceMap) {
this.map = new sourceMap.SourceMapGenerator({
file: opts.sourceMapName
});
this.map.setSourceContent(opts.sourceFileName, code);
} else {
this.map = null;
}
}
CodeGenerator.prototype.mark = function (node, locType) {
var loc = node.loc;
if (!loc) return; // no location info
var map = this.map;
if (!map) return; // no source map
map.addMapping({
source: this.opts.sourceFileName,
generated: {
line: this.line,
column: this.column
},
original: loc[locType]
});
};
CodeGenerator.prototype.newline = function () {
this.buf = this.buf.replace(/\n(\s+)$/, "\n");
this.buf += "\n";
this.line++;
};
CodeGenerator.prototype.semicolon = function () {
this.buf += ";";
this.column++;
};
CodeGenerator.prototype.keyword = function (name) {
this.push(name);
this.push(" ");
};
CodeGenerator.prototype.push = function (str, noIndent) {
if (this._indent && !noIndent) {
// we have an indent level and we aren't pushing a newline
var indent = this.getIndent();
// replace all newlines with newlines with the indentation
str = str.replace(/\n/g, "\n" + indent);
// we've got a newline before us so prepend on the indentation
if (this.isLast("\n")) str = indent + str;
}
var self = this;
_.each(str, function (cha) {
if (cha === "\n") {
self.line++;
self.column = 0;
} else {
self.column++;
}
});
this.buf += str;
};
CodeGenerator.prototype.isLast = function (cha) {
return _.last(this.buf) === cha;
};
CodeGenerator.prototype.getIndent = function () {
return util.repeat(this._indent * this.tabWidth);
};
CodeGenerator.prototype.indent = function () {
this._indent++;
};
CodeGenerator.prototype.dedent = function () {
this._indent--;
};
CodeGenerator.prototype.generate = function () {
var ast = this.ast;
this.print(ast);
var map = this.map;
if (map) map = map.toJSON();
return {
map: map,
ast: ast,
code: this.buf
};
};
CodeGenerator.prototype.buildPrint = function (parent) {
var self = this;
var print = function (node, opts) {
return self.print(node, parent, opts);
};
print.sequence = function (nodes, opts) {
return self.printSequence(print, nodes, opts);
};
return print;
};
CodeGenerator.prototype.printSequence = function (print, nodes, opts) {
var comments = this.ast.comments;
var tokens = this.ast.tokens;
var self = this;
opts = opts || {};
// calculate the whitespace between two tokens
var hasWhitespaceBetween = function (startToken, endToken) {
if (!startToken) return false;
var whitespace = false;
var start = startToken.end;
var end = endToken.start;
var sep = self.code.slice(start, end);
var lines = 0;
lines--; // take off the current line
// remove comments
_.each(comments, function (comment) {
// this comment is after the last token or befor ethe first
if (comment.end > end || comment.start < start) return;
var length = comment.end - comment.start;
// compute the relative positions of the comment within the sliced node
// string
var startRelative = comment.start - start;
var endRelative = comment.end - start;
// remove the line this comment ends with
if (comment.type === "Line") lines--;
// remove comment
sep = sep.slice(0, startRelative) + util.repeat(length) + sep.slice(endRelative);
});
// check if there was a newline between the two nodes
lines += _.size(sep.match(/\n/g));
return lines > 0;
};
var needsNewlineBefore = function (node) {
var startToken;
var endToken;
_.each(tokens, function (token, i) {
// this is the token this node starts with
if (node.start === token.start) {
startToken = tokens[i - 1];
endToken = token;
return false;
}
});
return hasWhitespaceBetween(startToken, endToken);
};
var needsNewlineAfter = function (node) {
var startToken;
var endToken;
_.each(tokens, function (token, i) {
// this is the token this node ends with
if (node.end === token.end) {
startToken = token;
endToken = tokens[i + 1];
return false;
}
});
return hasWhitespaceBetween(startToken, endToken);
};
opts.print = function (node, i) {
print(node, node && node.start != null && {
before: function () {
if (needsNewlineBefore(node)) self.newline();
},
after: function () {
if (needsNewlineAfter(node)) self.newline();
}
});
};
return this.printJoin(print, nodes, "\n", opts);
};
CodeGenerator.prototype.print = function (node, parent, opts) {
if (!node) return "";
opts = opts || {};
if (this[node.type]) {
this.printLeadingComments(node);
this.mark(node, "start");
if (opts.before) opts.before();
var needsParans = t.needsParans(node, parent);
if (needsParans) this.push("(");
this[node.type](node, this.buildPrint(node), parent);
if (needsParans) this.push(")");
if (opts.after) opts.after();
this.mark(node, "end");
this.printTrailingComments(node);
} else {
throw new ReferenceError("unknown node " + node.type + " " + JSON.stringify(node));
}
};
CodeGenerator.prototype.generateComment = function (comment) {
var val = comment.value;
if (comment.type === "Line") {
if (_.last(val) !== "\n") val += "\n";
return "//" + val;
} else {
return "/*" + val + "*/\n";
}
};
CodeGenerator.prototype.printTrailingComments = function (node) {
var self = this;
_.each(node.trailingComments, function (comment) {
self.push(self.generateComment(comment));
});
};
CodeGenerator.prototype.printLeadingComments = function (node) {
var self = this;
_.each(node.leadingComments, function (comment) {
self.push(self.generateComment(comment));
});
};
CodeGenerator.prototype.printJoin = function (print, nodes, sep, opts) {
opts = opts || {};
sep = sep || "\n";
var self = this;
var len = nodes.length;
if (opts.indent) self.indent();
_.each(nodes, function (node, i) {
if (opts.print) {
opts.print(node, i);
} else {
print(node);
}
if (opts.iterator) {
opts.iterator(node, i);
}
if (i < len - 1) {
self.push(sep);
}
});
if (opts.indent) self.dedent();
};
CodeGenerator.generators = {
arrayComprehensions: require("./generators/array-comprehensions"),
templateLiterals: require("./generators/template-literals"),
expressions: require("./generators/expressions"),
statements: require("./generators/statements"),
classes: require("./generators/classes"),
methods: require("./generators/methods"),
modules: require("./generators/modules"),
types: require("./generators/types"),
base: require("./generators/base"),
jsx: require("./generators/jsx")
};
_.each(CodeGenerator.generators, function (generator) {
_.extend(CodeGenerator.prototype, generator);
});