miller/pkg/parsing

This directory contains a single source file, mlr.bnf, which is the lexical/semantic grammar file for the Miller put/filter DSL (domain-specific language) using the GOCC framework. (In a classical Lex/Yacc framework, there would be separate mlr.l and mlr.y files; using GOCC, there is a single mlr.bnf file.)

All subdirectories of pkg/parsing/ are autogen code created by GOCC's processing of mlr.bnf. They are nonetheless committed to source control, since running GOCC takes quite a bit longer than the go build does, and the BNF file doesn't often change. (BNF is for Backus-Naur Form which is the phrasing of the grammar file that GOCC support.) See the top-level miller/go build scripts for how to rerun GOCC. As of this writing, it's

gocc -o pkg/parsing pkg/parsing/mlr.bnf

as invoked from the repo base directory -- however you should instead use

tools/build-dsl

Making changes to mlr.bnf requires several minutes to re-run GOCC. For experimental changes, please see the experiments directory.