ladybird/Libraries/LibJS/AST.cpp

/*
 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <LibJS/AST.h>
#include <LibJS/Function.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Value.h>
#include <stdio.h>

namespace JS {

Value ScopeNode::execute(Interpreter& interpreter) const
{
    return interpreter.run(*this);
}

Value FunctionDeclaration::execute(Interpreter& interpreter) const
{
    auto* function = new Function(name(), body());
    interpreter.global_object().put(m_name, Value(function));
    return Value(function);
}

Value CallExpression::execute(Interpreter& interpreter) const
{
    auto callee = interpreter.global_object().get(name());
    ASSERT(callee.is_object());
    auto* callee_object = callee.as_object();
    ASSERT(callee_object->is_function());
    auto& function = static_cast<Function&>(*callee_object);
    return interpreter.run(function.body());
}

Value ReturnStatement::execute(Interpreter& interpreter) const
{
    auto value = argument().execute(interpreter);
    interpreter.do_return();
    return value;
}

Value add(Value lhs, Value rhs)
{
    ASSERT(lhs.is_number());
    ASSERT(rhs.is_number());
    return Value(lhs.as_double() + rhs.as_double());
}

Value sub(Value lhs, Value rhs)
{
    ASSERT(lhs.is_number());
    ASSERT(rhs.is_number());
    return Value(lhs.as_double() - rhs.as_double());
}

Value BinaryExpression::execute(Interpreter& interpreter) const
{
    auto lhs_result = m_lhs->execute(interpreter);
    auto rhs_result = m_rhs->execute(interpreter);

    switch (m_op) {
    case BinaryOp::Plus:
        return add(lhs_result, rhs_result);
    case BinaryOp::Minus:
        return sub(lhs_result, rhs_result);
    }

    ASSERT_NOT_REACHED();
}

static void print_indent(int indent)
{
    for (int i = 0; i < indent * 2; ++i)
        putchar(' ');
}

void ASTNode::dump(int indent) const
{
    print_indent(indent);
    printf("%s\n", class_name());
}

void ScopeNode::dump(int indent) const
{
    ASTNode::dump(indent);
    for (auto& child : children())
        child.dump(indent + 1);
}

void BinaryExpression::dump(int indent) const
{
    ASTNode::dump(indent);
    m_lhs->dump(indent + 1);
    m_rhs->dump(indent + 1);
}

void CallExpression::dump(int indent) const
{
    print_indent(indent);
    printf("%s '%s'\n", class_name(), name().characters());
}

void Literal::dump(int indent) const
{
    print_indent(indent);
    printf("%d\n", (i32)m_value.as_double());
}

void FunctionDeclaration::dump(int indent) const
{
    print_indent(indent);
    printf("%s '%s'\n", class_name(), name().characters());
    body().dump(indent + 1);
}

void ReturnStatement::dump(int indent) const
{
    ASTNode::dump(indent);
    argument().dump(indent + 1);
}

}