J has a first-class citizen self tokenizer in the standard lib as a dedicated state machine ( ;: ) https://www.jsoftware.com/help/dictionary/d332.htm https://ww

J has a first-class citizen self tokenizer in the standard lib as a dedicated state machine ( ;: ) https://www.jsoftware.com/help/dictionary/d332.htm https://www.jsoftware.com/help/dictionary/d332.htm For an example of a very incomplete and largely suboptimal parser that uses the above: https://github.com/Rscho314/J-compiler/blob/master/ast.ijs https://github.com/Rscho314/J-compiler/blob/master/ast.ijs