Java 类org.mozilla.javascript.ast.ArrayComprehension 实例源码

private void print(ArrayComprehension node) throws IOException {
    writer.append("[");
    for (ArrayComprehensionLoop loop : node.getLoops()) {
        writer.append("for").ws().append("(");
        print(loop.getIterator());
        writer.append(" of ");
        print(loop.getIteratedObject());
        writer.append(')');
    }
    if (node.getFilter() != null) {
        writer.append("if").ws().append("(");
        print(node.getFilter());
        writer.append(")");
    }
    print(node.getResult());
    writer.append(']');
}

/**
 * Parse a JavaScript 1.7 Array comprehension.
 * @param result the first expression after the opening left-bracket
 * @param pos start of LB token that begins the array comprehension
 * @return the array comprehension or an error node
 */
private AstNode arrayComprehension(AstNode result, int pos)
    throws IOException
{
    List<ArrayComprehensionLoop> loops =
            new ArrayList<ArrayComprehensionLoop>();
    while (peekToken() == Token.FOR) {
        loops.add(arrayComprehensionLoop());
    }
    int ifPos = -1;
    ConditionData data = null;
    if (peekToken() == Token.IF) {
        consumeToken();
        ifPos = ts.tokenBeg - pos;
        data = condition();
    }
    mustMatchToken(Token.RB, "msg.no.bracket.arg");
    ArrayComprehension pn = new ArrayComprehension(pos, ts.tokenEnd - pos);
    pn.setResult(result);
    pn.setLoops(loops);
    if (data != null) {
        pn.setIfPosition(ifPos);
        pn.setFilter(data.condition);
        pn.setFilterLp(data.lp - pos);
        pn.setFilterRp(data.rp - pos);
    }
    return pn;
}

/**
 * Parse a JavaScript 1.7 Array comprehension.
 * @param result the first expression after the opening left-bracket
 * @param pos start of LB token that begins the array comprehension
 * @return the array comprehension or an error node
 */
private AstNode arrayComprehension(AstNode result, int pos)
    throws IOException
{
    List<ArrayComprehensionLoop> loops =
            new ArrayList<ArrayComprehensionLoop>();
    while (peekToken() == Token.FOR) {
        loops.add(arrayComprehensionLoop());
    }
    int ifPos = -1;
    ConditionData data = null;
    if (peekToken() == Token.IF) {
        consumeToken();
        ifPos = ts.tokenBeg - pos;
        data = condition();
    }
    mustMatchToken(Token.RB, "msg.no.bracket.arg");
    ArrayComprehension pn = new ArrayComprehension(pos, ts.tokenEnd - pos);
    pn.setResult(result);
    pn.setLoops(loops);
    if (data != null) {
        pn.setIfPosition(ifPos);
        pn.setFilter(data.condition);
        pn.setFilterLp(data.lp - pos);
        pn.setFilterRp(data.rp - pos);
    }
    return pn;
}

private Node transformArrayComp(ArrayComprehension node) {
    // An array comprehension expression such as
    //
    //   [expr for (x in foo) for each ([y, z] in bar) if (cond)]
    //
    // is rewritten approximately as
    //
    // new Scope(ARRAYCOMP) {
    //   new Node(BLOCK) {
    //     let tmp1 = new Array;
    //     for (let x in foo) {
    //       for each (let tmp2 in bar) {
    //         if (cond) {
    //           tmp1.push([y, z] = tmp2, expr);
    //         }
    //       }
    //     }
    //   }
    //   createName(tmp1)
    // }

    int lineno = node.getLineno();
    Scope scopeNode = createScopeNode(Token.ARRAYCOMP, lineno);
    String arrayName = currentScriptOrFn.getNextTempName();
    pushScope(scopeNode);
    try {
        defineSymbol(Token.LET, arrayName, false);
        Node block = new Node(Token.BLOCK, lineno);
        Node newArray = createCallOrNew(Token.NEW, createName("Array"));
        Node init = new Node(Token.EXPR_VOID,
                             createAssignment(Token.ASSIGN,
                                              createName(arrayName),
                                              newArray),
                             lineno);
        block.addChildToBack(init);
        block.addChildToBack(arrayCompTransformHelper(node, arrayName));
        scopeNode.addChildToBack(block);
        scopeNode.addChildToBack(createName(arrayName));
        return scopeNode;
    } finally {
        popScope();
    }
}

private Node transformArrayComp(ArrayComprehension node) {
    // An array comprehension expression such as
    //
    //   [expr for (x in foo) for each ([y, z] in bar) if (cond)]
    //
    // is rewritten approximately as
    //
    // new Scope(ARRAYCOMP) {
    //   new Node(BLOCK) {
    //     let tmp1 = new Array;
    //     for (let x in foo) {
    //       for each (let tmp2 in bar) {
    //         if (cond) {
    //           tmp1.push([y, z] = tmp2, expr);
    //         }
    //       }
    //     }
    //   }
    //   createName(tmp1)
    // }

    int lineno = node.getLineno();
    Scope scopeNode = createScopeNode(Token.ARRAYCOMP, lineno);
    String arrayName = currentScriptOrFn.getNextTempName();
    pushScope(scopeNode);
    try {
        defineSymbol(Token.LET, arrayName, false);
        Node block = new Node(Token.BLOCK, lineno);
        Node newArray = createCallOrNew(Token.NEW, createName("Array"));
        Node init = new Node(Token.EXPR_VOID,
                             createAssignment(Token.ASSIGN,
                                              createName(arrayName),
                                              newArray),
                             lineno);
        block.addChildToBack(init);
        block.addChildToBack(arrayCompTransformHelper(node, arrayName));
        scopeNode.addChildToBack(block);
        scopeNode.addChildToBack(createName(arrayName));
        return scopeNode;
    } finally {
        popScope();
    }
}