gen.sh

#!/usr/bin/env bash
set -euo pipefail
cd "$(dirname "${BASH_SOURCE[0]}")"

if ! command -v goyacc &>/dev/null; then
    echo "installing goyacc"
    if ! go install -v -mod=readonly golang.org/x/tools/cmd/goyacc@v0.30.0; then
        echo "failed to install goyacc" >&2
        exit 1
    fi
fi

if ! command -v ragel &>/dev/null; then
    install_cmd=()
    if command -v apt &>/dev/null; then
        install_cmd=(sudo apt-get install ragel)
    elif command -v brew &>/dev/null; then
        install_cmd=(env HOMEBREW_NO_AUTO_UPDATE=1 HOMEBREW_NO_INSTALL_CLEANUP=1 brew install ragel)
    fi

    installed=0
    if ((${#install_cmd[@]} > 0)); then
        echo "installing ragel: ${install_cmd[*]}"
        "${install_cmd[@]}"
        # shellcheck disable=SC2181
        if [[ $? -eq 0 ]]; then
            installed=1
        fi
    fi
    if [[ $installed -eq 0 ]]; then
        echo "please install ragel using your package manager" >&2
        exit 1
    fi
fi

echo "⚙️ generating lexer"
ragel -Z lexer.rl
# add autogenerated comment
sed -i.bak '1s#^#// Code generated by ragel. DO NOT EDIT.\n#' lexer.go
gofmt -w lexer.go
rm lexer.go.bak

echo "⚙️ generating parser"
goyacc -v y.output -o parser.gen.go -p rule parser.y
# add a new method to the interface generated by goyacc
sed -i.bak '/type ruleLexer interface {/a Result(n Rule)' parser.gen.go
gofmt -w parser.gen.go
rm parser.gen.go.bak

echo "✅ done!"