| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.apache.freemarker.core; |
| |
| /** |
| * Superclass of all AST (Abstract Syntax Tree) nodes. |
| * <p> |
| * The AST is a tree data structure that represent the complete content of a template (static content, directive calls, |
| * interpolations and the expressions inside them, possibly comments as well), without the complexities of syntactical |
| * details. The AST is generated from the source code (which is text) by the parser of the {@link TemplateLanguage}, |
| * and focuses on the meaning of the template. Thus, if the same template is rewritten in different template languages |
| * (like F3AH is converted to F3SH), the resulting AST-s will remain practically identical. |
| * <p> |
| * When a {@link Template} is processed, FreeMarker executes the AST directly. (In theory the AST could be translated |
| * further to byte code, FreeMarker doesn't try to do that, at least currently.) |
| * <p> |
| * The AST can also be used to analyze the content of templates, such as to discover its dependencies (on data-model |
| * variables, on other templates). |
| */ |
| //TODO [FM3] will be public |
| abstract class ASTNode { |
| |
| private Template template; |
| int beginColumn, beginLine, endColumn, endLine; |
| |
| /** This is needed for an ?eval hack; the expression AST nodes will be the descendants of the template, however, |
| * we can't give their position in the template, only in the dynamic string that's evaluated. That's signaled |
| * by a negative line numbers, starting from this constant as line 1. */ |
| static final int RUNTIME_EVAL_LINE_DISPLACEMENT = -1000000000; |
| |
| final void setLocation(Template template, Token begin, Token end) { |
| setLocation(template, begin.beginColumn, begin.beginLine, end.endColumn, end.endLine); |
| } |
| |
| final void setLocation(Template template, Token tagBegin, Token tagEnd, TemplateElements children) { |
| ASTElement lastChild = children.getLast(); |
| if (lastChild != null) { |
| // [<#if exp>children]<#else> |
| setLocation(template, tagBegin, lastChild); |
| } else { |
| // [<#if exp>]<#else> |
| setLocation(template, tagBegin, tagEnd); |
| } |
| } |
| |
| final void setLocation(Template template, Token begin, ASTNode end) { |
| setLocation(template, begin.beginColumn, begin.beginLine, end.endColumn, end.endLine); |
| } |
| |
| final void setLocation(Template template, ASTNode begin, Token end) { |
| setLocation(template, begin.beginColumn, begin.beginLine, end.endColumn, end.endLine); |
| } |
| |
| final void setLocation(Template template, ASTNode begin, ASTNode end) { |
| setLocation(template, begin.beginColumn, begin.beginLine, end.endColumn, end.endLine); |
| } |
| |
| void setLocation(Template template, int beginColumn, int beginLine, int endColumn, int endLine) { |
| this.template = template; |
| this.beginColumn = beginColumn; |
| this.beginLine = beginLine; |
| this.endColumn = endColumn; |
| this.endLine = endLine; |
| } |
| |
| // Package visible constructor to prevent extending this class outside FreeMarker |
| ASTNode() { } |
| |
| /** |
| * The template that contains this node. |
| */ |
| public Template getTemplate() { |
| return template; |
| } |
| |
| /** |
| * 1-based column number of the last character of this node in the source code. 0 if not available. |
| */ |
| public final int getBeginColumn() { |
| return beginColumn; |
| } |
| |
| /** |
| * 1-based line number of the first character of this node in the source code. 0 if not available. |
| */ |
| // TODO [FM3] No negative number hack in ?eval and such. |
| public final int getBeginLine() { |
| return beginLine; |
| } |
| |
| /** |
| * 1-based column number of the first character of this node in the source code. 0 if not available. |
| */ |
| public final int getEndColumn() { |
| return endColumn; |
| } |
| |
| /** |
| * 1-based line number of the last character of this node in the source code. 0 if not available. |
| */ |
| public final int getEndLine() { |
| return endLine; |
| } |
| |
| final String getSource() { |
| String s; |
| if (template != null) { |
| s = template.getSource(beginColumn, beginLine, endColumn, endLine); |
| } else { |
| s = null; |
| } |
| |
| // Can't just return null for backward-compatibility... |
| return s != null ? s : getCanonicalForm(); |
| } |
| |
| @Override |
| public final String toString() { |
| String s; |
| return (s = getSource()) != null ? s : getCanonicalForm(); |
| } |
| |
| /** |
| * @return whether the point in the template file specified by the |
| * column and line numbers is contained within this template object. |
| */ |
| public boolean contains(int column, int line) { |
| if (line < beginLine || line > endLine) { |
| return false; |
| } |
| if (line == beginLine) { |
| if (column < beginColumn) { |
| return false; |
| } |
| } |
| if (line == endLine) { |
| if (column > endColumn) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| ASTNode copyLocationFrom(ASTNode from) { |
| template = from.template; |
| beginColumn = from.beginColumn; |
| beginLine = from.beginLine; |
| endColumn = from.endColumn; |
| endLine = from.endLine; |
| return this; |
| } |
| |
| /** |
| * Template source code generated from the AST of this node. |
| * When parsed, it should result in a practically identical AST that does the same as the original |
| * source, assuming that you turn off automatic white-space removal when parsing the canonical form. |
| * |
| * @see ASTElement#getLabelWithParameters() |
| * @see #getLabelWithoutParameters() |
| */ |
| // TODO [FM3] The whitespace problem isn't OK; do pretty-formatting, outside core if too big. |
| abstract public String getCanonicalForm(); |
| |
| /** |
| * A very sort single-line string that describes what kind of AST node this is, without describing any |
| * embedded expression or child element. Examples: {@code "#if"}, {@code "+"}, <code>"${...}</code>. These values should |
| * be suitable as tree node labels in a tree view. Yet, they should be consistent and complete enough so that an AST |
| * that is equivalent with the original could be reconstructed from the tree view. Thus, for literal values that are |
| * leaf nodes the symbols should be the canonical form of value. |
| * |
| * @see #getCanonicalForm() |
| * @see ASTElement#getLabelWithParameters() |
| */ |
| public abstract String getLabelWithoutParameters(); |
| |
| /** |
| * Returns highest valid parameter index + 1. So one should scan indexes with {@link #getParameterValue(int)} |
| * starting from 0 up until but excluding this. For example, for the binary "+" operator this will give 2, so the |
| * legal indexes are 0 and 1. Note that if a parameter is optional in a template-object-type and happens to be |
| * omitted in an instance, this will still return the same value and the value of that parameter will be |
| * {@code null}. |
| */ |
| abstract int getParameterCount(); |
| |
| /** |
| * Returns the value of the parameter identified by the index. For example, the binary "+" operator will have an |
| * LHO {@link ASTExpression} at index 0, and and RHO {@link ASTExpression} at index 1. Or, the binary "." operator will |
| * have an LHO {@link ASTExpression} at index 0, and an RHO {@link String}(!) at index 1. Or, the {@code #include} |
| * directive will have a path {@link ASTExpression} at index 0, a "parse" {@link ASTExpression} at index 1, etc. |
| * |
| * <p>The index value doesn't correspond to the source-code location in general. It's an arbitrary identifier |
| * that corresponds to the role of the parameter instead. This also means that when a parameter is omitted, the |
| * index of the other parameters won't shift. |
| * |
| * @return {@code null} or any kind of {@link Object}, very often an {@link ASTExpression}. However, if there's |
| * a {@link ASTNode} stored inside the returned value, it must itself be be a {@link ASTNode} |
| * too, otherwise the AST couldn't be (easily) fully traversed. That is, non-{@link ASTNode} values |
| * can only be used for leafs. |
| * |
| * @throws IndexOutOfBoundsException if {@code idx} is less than 0 or not less than {@link #getParameterCount()}. |
| */ |
| abstract Object getParameterValue(int idx); |
| |
| /** |
| * Returns the role of the parameter at the given index, like {@link ParameterRole#LEFT_HAND_OPERAND}. |
| * |
| * As of this writing (2013-06-17), for directive parameters it will always give {@link ParameterRole#UNKNOWN}, |
| * because there was no need to be more specific so far. This should be improved as need. |
| * |
| * @throws IndexOutOfBoundsException if {@code idx} is less than 0 or not less than {@link #getParameterCount()}. |
| */ |
| abstract ParameterRole getParameterRole(int idx); |
| |
| } |
