Math Parser

A mathematical expression parser and evaluator powered by Pratt's top-down operator precedence.

Features

• C99 compliant with no dependencies.
• Symbol table for pre-loaded constants (pi and e) and user-defined variables.
• Supports standard math functions (sin, sqrt, log, etc.).
• Usable as a one-shot CLI tool or an interactive REPL.
• Compiles to a .a file for easy integration into other C projects.

Building

The project uses a Makefile and requires gcc to compile. To generate the static library and the executable binary, there are two options.

• Release mode: Use make to build with maximum optimization.
• Debug mode: Use make DEBUG=1 to build with debug symbols and no optimizations.

This will output lib/mode/libmathparser.a and bin/mode/parser, where mode is either release or debug. Object files are placed in build/mode/.

Usage

CLI

Pass an expression as a quoted string to evaluate it immediately.

./parser "ln(e^(-1/3))"

REPL

Run without arguments to enter the REPL. This allows for AST visualization and variable assignment. Type .help to see all available commands.

> x = y = 12
12.000000
> sqrt(x + y + 1)
5.000000

Library

Include the necessary headers (parser.h and environment.h from include/) and initialize both the parser and the symbol table.

Parser parser = parser_init();
SymbolTable symbol_table = symbol_table_init();

Add variables to the symbol table, update their value and retrieve them.

symbol_table_set(&symbol_table, "my_var", 6, 9.5);  // Create new
symbol_table_set(&symbol_table, "my_var", 6, 30.8); // Update
symbol_table_get(&symbol_table, "my_var", 6);       // Fetch

Parse an expression and evaluate the resulting AST.

Node *root = parser_parse(&parser, "sin(pi*3-0.2)");
double result = env_evaluate(root, &symbol_table);

License

This project is available under the MIT License.