syntax_analysis

Syntax Analysis

Content

1. Introduction
2. Context-free grammar
3. Write a grammar
4. Some issues

How to test grammar using grun

1. Step 1: Exporting classpath of the jar and creating alias

# Exporting classpath of the jar and creating alias
$ export CLASSPATH=".:path_to/antlr-*-complete.jar:$CLASSPATH"
$ alias antlr4='java -Xmx500M -cp "path_to/antlr-*-complete.jar:$CLASSPATH" org.antlr.v4.Tool'
$ alias grun='java org.antlr.v4.runtime.misc.TestRig'

2. Step 2: Testing if jar is accessible or not

$ java org.antlr.v4.Tool
# or
$ java -jar path_to/antlr-*-complete.jar
# or
$ antlr4

If it shows:

ANTLR Parser Generator Version 4.7
so on ...

then it was successful

3. Step 3: Running the antlr tool on file

$ antlr4 MC.g4 

It will auto generate files *.tokens *.java

4. Step 4: Compile all the java files by

$ javac MC*.java

5. Step 5: Draw parser tree by following command:

$ grun MC program -f path_to/test.txt -gui

Now, we have the parse tree as shown below