initial commit

input/JavaScriptBaseLexer.java

@@ -0,0 +1,119 @@
+package org.bdware.sc.parser;
+import org.antlr.v4.runtime.*;
+import java.util.Stack;
+public abstract class JavaScriptBaseLexer extends Lexer
+{
+    /**
+     * Stores values of nested modes. By default mode is strict or
+     * defined externally (useStrictDefault)
+     */
+    private Stack<Boolean> scopeStrictModes = new Stack<Boolean>();
+
+    private Token lastToken = null;
+    /**
+     * Default value of strict mode
+     * Can be defined externally by setUseStrictDefault
+     */
+    private boolean useStrictDefault = false;
+    /**
+     * Current value of strict mode
+     * Can be defined during parsing, see StringFunctions.js and StringGlobal.js samples
+     */
+    private boolean useStrictCurrent = false;
+
+    public JavaScriptBaseLexer(CharStream input) {
+        super(input);
+    }
+
+    public boolean getStrictDefault() {
+        return useStrictDefault;
+    }
+
+    public void setUseStrictDefault(boolean value) {
+        useStrictDefault = value;
+        useStrictCurrent = value;
+    }
+
+    public boolean IsStrictMode() {
+        return useStrictCurrent;
+    }
+
+    /**
+     * Return the next token from the character stream and records this last
+     * token in case it resides on the default channel. This recorded token
+     * is used to determine when the lexer could possibly match a regex
+     * literal. Also changes scopeStrictModes stack if tokenize special
+     * string 'use strict';
+     *
+     * @return the next token from the character stream.
+     */
+    @Override
+    public Token nextToken() {
+        Token next = super.nextToken();
+
+        if (next.getChannel() == Token.DEFAULT_CHANNEL) {
+            // Keep track of the last token on the default channel.
+            this.lastToken = next;
+        }
+
+        return next;
+    }
+
+    protected void ProcessOpenBrace()
+    {
+        useStrictCurrent = scopeStrictModes.size() > 0 && scopeStrictModes.peek() ? true : useStrictDefault;
+        scopeStrictModes.push(useStrictCurrent);
+    }
+
+    protected void ProcessCloseBrace()
+    {
+        useStrictCurrent = scopeStrictModes.size() > 0 ? scopeStrictModes.pop() : useStrictDefault;
+    }
+
+    protected void ProcessStringLiteral()
+    {
+        if (lastToken == null || lastToken.getType() == JavaScriptLexer.OpenBrace)
+        {
+            String text = getText();
+            if (text.equals("\"use strict\"") || text.equals("'use strict'"))
+            {
+                if (scopeStrictModes.size() > 0)
+                    scopeStrictModes.pop();
+                useStrictCurrent = true;
+                scopeStrictModes.push(useStrictCurrent);
+            }
+        }
+    }
+
+    /**
+     * Returns {@code true} if the lexer can match a regex literal.
+     */
+    protected boolean IsRegexPossible() {
+                                       
+        if (this.lastToken == null) {
+            // No token has been produced yet: at the start of the input,
+            // no division is possible, so a regex literal _is_ possible.
+            return true;
+        }
+        
+        switch (this.lastToken.getType()) {
+            case JavaScriptLexer.Identifier:
+            case JavaScriptLexer.NullLiteral:
+            case JavaScriptLexer.BooleanLiteral:
+            case JavaScriptLexer.This:
+            case JavaScriptLexer.CloseBracket:
+            case JavaScriptLexer.CloseParen:
+            case JavaScriptLexer.OctalIntegerLiteral:
+            case JavaScriptLexer.DecimalLiteral:
+            case JavaScriptLexer.HexIntegerLiteral:
+            case JavaScriptLexer.StringLiteral:
+            case JavaScriptLexer.PlusPlus:
+            case JavaScriptLexer.MinusMinus:
+                // After any of the tokens above, no regex literal can follow.
+                return false;
+            default:
+                // In all other cases, a regex literal _is_ possible.
+                return true;
+        }
+    }
+}