babel/lib/6to5/generator.js
2014-11-07 12:32:15 +11:00

455 lines
10 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 util = require("./util");
var t = require("./types");
var _ = require("lodash");
function CodeGenerator(code, ast, opts) {
opts = opts || {};
this.tabWidth = 2;
this.comments = ast.comments || [];
this.tokens = _.sortBy(_.compact([].concat(ast.tokens, this.comments)), "start");
this.code = code;
this.opts = opts;
this.ast = ast;
this.buf = "";
this.usedLineWhitespace = [];
this._indent = 0;
this.column = 0;
this.line = 1;
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, type) {
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[type]
});
};
CodeGenerator.prototype.newline = function (i, removeLast) {
if (!this.buf) return;
if (_.isBoolean(i)) {
removeLast = i;
i = null;
}
if (_.isNumber(i)) {
var self = this;
_.times(i, function () {
self.newline(null, removeLast);
});
return;
}
if (removeLast && this.isLast("\n")) this.removeLast("\n");
this.removeLast(" ");
this.buf = this.buf.replace(/\n(\s+)$/, "\n");
this._push("\n");
};
CodeGenerator.prototype.removeLast = function (cha) {
if (!this.isLast(cha)) return;
this.buf = this.buf.slice(0, -1);
if (cha === "\n") {
this.line--;
} else {
this.column--;
}
};
CodeGenerator.prototype.semicolon = function () {
this.push(";");
};
CodeGenerator.prototype.ensureSemicolon = function () {
if (!this.isLast(";")) this.semicolon();
};
CodeGenerator.prototype.rightBrace = function () {
this.newline(true);
this.push("}");
};
CodeGenerator.prototype.keyword = function (name) {
this.push(name);
this.push(" ");
};
CodeGenerator.prototype.space = function () {
if (this.buf && !this.isLast([" ", "\n"])) {
this.push(" ");
}
};
CodeGenerator.prototype.printAndIndentOnComments = function (print, node) {
var indent = !!node.leadingComments;
if (indent) this.indent();
print(node);
if (indent) this.dedent();
};
CodeGenerator.prototype.printBlock = function (print, node) {
if (t.isEmptyStatement(node)) {
this.semicolon();
} else {
this.push(" ");
print(node);
}
};
CodeGenerator.prototype.push = function (str, noIndent) {
if (this._indent && !noIndent && str !== "\n") {
// 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;
}
this._push(str);
};
CodeGenerator.prototype._push = function (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, trimRight) {
var buf = this.buf;
if (trimRight) buf = buf.trimRight();
var chars = [].concat(cha);
return _.contains(chars, _.last(buf));
};
CodeGenerator.prototype.getIndent = function () {
return util.repeat(this.indentSize());
};
CodeGenerator.prototype.indentSize = function () {
return 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);
this.buf = this.buf.trimRight();
this.buf = this.buf.replace(/\{\n\n/g, "{\n");
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) {
opts = opts || {};
opts.statement = true;
return self.printJoin(print, nodes, opts);
};
return print;
};
CodeGenerator.prototype.needsNewlineBefore = function (node) {
var startToken;
var endToken;
var tokens = this.tokens;
_.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 this.hasWhitespaceBetween(startToken, endToken);
};
CodeGenerator.prototype.needsNewlineAfter = function (node) {
var startToken;
var endToken;
var tokens = this.tokens;
_.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 this.hasWhitespaceBetween(startToken, endToken);
};
CodeGenerator.prototype.hasWhitespaceBetween = function (startToken, endToken) {
if (!endToken) return false;
var start = startToken ? startToken.loc.end.line : 1;
var end = endToken.loc.start.line;
var sep = this.code.slice(start, end);
var lines = 0;
for (var line = start; line < end; line++) {
if (!_.contains(this.usedLineWhitespace, line)) {
this.usedLineWhitespace.push(line);
lines++;
}
}
return lines;
};
CodeGenerator.prototype.print = function (node, parent, opts) {
if (!node) return "";
var self = this;
opts = opts || {};
var newline = function (leading, fn) {
var ignoreDuplicates = false;
if (!opts.statement) {
if (t.isUserWhitespacable(node)) {
ignoreDuplicates = true;
} else {
return;
}
}
var lines = 0;
if (node.start != null) {
// user node
lines = fn.call(self, node);
} else {
// generated node
if (!leading) lines++; // definently include a single line
var needs = t.needsWhitespaceAfter;
if (leading) needs = t.needsWhitespaceBefore;
if (needs(node, opts.statement)) lines++;
}
self.newline(lines, ignoreDuplicates);
};
if (this[node.type]) {
this.printLeadingComments(node, parent);
newline(true, this.needsNewlineBefore);
if (opts.before) opts.before();
this.mark(node, "start");
var needsParans = t.needsParans(node, parent);
if (needsParans) this.push("(");
this[node.type](node, this.buildPrint(node), parent);
if (needsParans) this.push(")");
this.mark(node, "end");
if (opts.after) opts.after();
newline(false, this.needsNewlineAfter);
this.printTrailingComments(node, parent);
} else {
throw new ReferenceError("unknown node " + node.type + " " + JSON.stringify(node));
}
};
CodeGenerator.prototype.generateComment = function (comment) {
var val = comment.value;
if (comment.type === "Line") {
val = "//" + val;
} else {
val = "/*" + val + "*/";
}
return val;
};
CodeGenerator.prototype.printTrailingComments = function (node, parent) {
this._printComments(this.getComments("trailingComments", node, parent));
};
CodeGenerator.prototype.printLeadingComments = function (node, parent) {
this._printComments(this.getComments("leadingComments", node, parent));
};
CodeGenerator.prototype.getComments = function (key, node, parent) {
if (t.isExpressionStatement(parent)) {
return [];
}
var comments = [];
var nodes = [node];
var self = this;
if (t.isExpressionStatement(node)) {
nodes.push(node.argument);
}
_.each(nodes, function (node) {
comments = comments.concat(self._getComments(key, node));
});
return comments;
};
CodeGenerator.prototype._getComments = function (key, node) {
return (node && node[key]) || [];
};
CodeGenerator.prototype._printComments = function (comments) {
if (!comments || !comments.length) return;
var self = this;
_.each(comments, function (comment, i) {
// whitespace before
self.newline(self.needsNewlineBefore(comment));
var val = self.generateComment(comment);
if (self.column && !self.isLast(["\n", " ", "[", "{"])) {
self._push(" ");
}
//
var offset = comment.loc.start.column;
if (offset) {
var newlineRegex = new RegExp("\\n\\s{1," + offset + "}", "g");
val = val.replace(newlineRegex, "\n");
}
var indent = Math.max(self.indentSize(), self.column);
val = val.replace(/\n/g, "\n" + util.repeat(indent));
if (self.column == 0) {
val = self.getIndent() + val;
}
//
self._push(val);
// whitespace after
self.newline(self.needsNewlineAfter(comment));
});
};
CodeGenerator.prototype.printJoin = function (print, nodes, opts) {
opts = opts || {};
var self = this;
var len = nodes.length;
if (opts.indent) self.indent();
_.each(nodes, function (node, i) {
print(node, {
statement: opts.statement,
after: function () {
if (opts.iterator) {
opts.iterator(node, i);
}
if (opts.separator && i < len - 1) {
self.push(opts.separator);
}
}
});
});
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);
});