Building an Arithmetic Expression Parser with Precedence Levels

To extend a simple calculator to evaluate full arithmetic expressions—including those with mixed operators and parentheses—we structure the grammar in hierarchical layers, each representing a different precedence level. This ensures correct evaluation order without requiring explicit parentheses in every case. The grammar is divided into three ...

Posted on Thu, 18 Jun 2026 17:14:09 +0000 by psy

Defining Reusable Grammar Macros in LALRPOP

When constructing formal grammars, developers frequently encounter repetitive syntactic patterns. A typical scenario involves parsing delimiter-separated sequences, such as lists of identifiers or arithmetic expressions. Manually expanding these rules results in verbose definitions that are difficult to maintain and prone to copy-paste errors. ...

Posted on Wed, 03 Jun 2026 17:12:04 +0000 by pontiac007

Integrating Logos with LALRPOP for Custom Lexing

Building a lexer from scratch can be complex and error-prone. Instead, leveraging existing libraries like Logos simplifies tokenization significantly. This guide demonstrates how to integrate Logos as the lexer for a toy language parsed with LALRPOP. Consider the follownig input: var a = 42; var b = 23; # a comment print (a - b); Depandency S ...

Posted on Wed, 27 May 2026 22:45:42 +0000 by sloth456