AST demo

Demonstrates two ways to create an Abstract Syntax Tree:

recursively transform the parse tree
have the parser build the AST directly

How to run

./astdemo -b builds an AST by recursive transformation
./astdemo -2 builds an AST directly in the parser

Example input (input as standard input, or in a file):

a - b * 3 - 4 * c + 5

Expected AST (for both -b and -2 options):

ADD
+--SUB
|  +--SUB
|  |  +--VARREF[a]
|  |  +--MULTIPLY
|  |     +--VARREF[b]
|  |     +--INT_LITERAL[3]
|  +--MULTIPLY
|     +--INT_LITERAL[4]
|     +--VARREF[c]
+--INT_LITERAL[5]

The -p option prints the parse tree. Parse tree for example input:

E
+--T
|  +--F
|  |  +--IDENTIFIER[a]
|  +--T'
+--E'
   +--MINUS[-]
   +--T
   |  +--F
   |  |  +--IDENTIFIER[b]
   |  +--T'
   |     +--TIMES[*]
   |     +--F
   |     |  +--INTEGER_LITERAL[3]
   |     +--T'
   +--E'
      +--MINUS[-]
      +--T
      |  +--F
      |  |  +--INTEGER_LITERAL[4]
      |  +--T'
      |     +--TIMES[*]
      |     +--F
      |     |  +--IDENTIFIER[c]
      |     +--T'
      +--E'
         +--PLUS[+]
         +--T
         |  +--F
         |  |  +--INTEGER_LITERAL[5]
         |  +--T'
         +--E'

daveho/astdemo

AST demo