alumik / parse-tree-java

A simple parse tree generator for any user-defined LR(1) programming language

LR(1) Parse Tree Generator

This project is heavily inspired by LYRON, a universal compiler framework.

Usage

Modify config.yml if necessary, place your test file, e.g., test.txt, and then execute

cat test.txt | java -jar parse-tree.jar

You can also execute the jar file directly and input your test code in the console.

Examples

Lexical Analysis

NFA to DFA

Take the regular expression (a|b)*abb for example.

1. Create an NFA.

   

2. Convert the NFA to a DFA.

   

Merge multiple NFAs

Take the regular expressions a*b+, a, abb for example.

1. Create three NFAs and combine them into one large NFA.

   

2. Convert the DFA to DFA.

   

Creating Parse Tree

1. Get the predefined grammar.

   1. S'->S
   2. S->CβBA
   3. A->Aαβ
   4. A->αβ
   5. B->C
   6. B->Dβ
   7. C->α
   8. D->α
   

2. Write a config file (in YAML format).

   nonterminalSymbols:
     # ? name
     ? A
     ? B
     ? C
     ? D
     ? S
   terminalSymbols:
     # name: regex
     α: a
     β: b
   ignoredSymbols:
   startSymbol: S
   productions:
     # - left part -> right part
     - S -> C β B A
     - A -> A α β
     - A -> α β
     - B -> C
     - B -> D β
     - C -> α
     - D -> α

3. Generate the parse table.

   	ACTION			GOTO
   	α	β	$	S	A	B	C	D
   0	s1			3			2
   1		r7
   2		s4
   3			acc
   4	s5					6	7	8
   5	r7	r8
   6	s10				9
   7	r5
   8		s11
   9	s12		r2
   10		s13
   11	r6
   12		s14
   13	r4		r4
   14	r3		r3

4. Generate the parse tree.

   The input string is abababab.