joekreu
joekreu
/ 1_infix_parser.py
Last active
April 16, 2022 13:10
Iterative and recursive precedence parsers for infix expressions, in Python. This gist contains four scripts with increasing complexity.
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| #! /usr/bin/env python3 | |
| ''' Script for precedence climbing parsing for infix operators, based | |
| on binding powers; iterative and recursive implementation. Binding | |
| powers are in range 1 to 99. - Separate tokens in DEMOS by spaces. | |
| ''' | |
| LBP = {"+": 14, "*": 17, "^": 21, ":=": 22, "$END": -1} | |
| RBP = {"+": 15, "*": 18, "^": 20, ":=": 8} | |
| DEMOS = ['x + 3.4 * y', 'a + b + c', 'n ^ m ^ k', '3 * x := v + 1'] |