Bazel build rules for GNU Bison

This Bazel ruleset allows GNU Bison to be integrated into a Bazel build. It can be used to generate parsers in C, C++, or Java.

API reference: docs/rules_bison.md

Setup

As a module dependency (bzlmod)

Add the following to your MODULE.bazel:

bazel_dep(name = "rules_bison", version = "0.3")

To specify a version or build with additional C compiler options, use the bison_repository_ext module extension:

bison = use_extension(
    "@rules_bison//bison/extensions:bison_repository_ext.bzl",
    "bison_repository_ext",
)
bison.repository(
    name = "bison",
    version = "3.3.2",
    extra_copts = ["-O3"],
)
use_repo(bison, "bison")
register_toolchains("@bison//:toolchain")

Note that repository names registered with a given bzlmod module extension must be unique within the scope of that extension. See the Bazel module extensions documentation for more details.

As a workspace dependency

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "rules_m4",
    sha256 = "10ce41f150ccfbfddc9d2394ee680eb984dc8a3dfea613afd013cfb22ea7445c",
    urls = ["https://github.com/jmillikin/rules_m4/releases/download/v0.2.3/rules_m4-v0.2.3.tar.xz"],
)

load("@rules_m4//m4:m4.bzl", "m4_register_toolchains")

m4_register_toolchains(version = "1.4.18")

http_archive(
    name = "rules_bison",
    # Obtain the package checksum from the release page:
    # https://github.com/jmillikin/rules_bison/releases/tag/v0.3
    sha256 = "",
    urls = ["https://github.com/jmillikin/rules_bison/releases/download/v0.3/rules_bison-v0.3.tar.xz"],
)

load("@rules_bison//bison:bison.bzl", "bison_register_toolchains")

bison_register_toolchains(version = "3.3.2")

Examples

Integrating Bison into a C/C++ dependency graph:

load("@rules_bison//bison:bison.bzl", "bison_cc_library")

bison_cc_library(
    name = "hello_parser",
    src = "hello.y",
)

cc_binary(
    name = "hello",
    deps = [":hello_parser"],
)

Integrating Bison into a Java dependency graph:

load("@rules_bison//bison:bison.bzl", "bison_java_library")

bison_java_library(
    name = "HelloParser",
    src = "hello.y",
)

java_binary(
    name = "Hello",
    srcs = ["Hello.java"],
    main_class = "Hello",
    deps = [":HelloParser"],
)

Generating .c / .h / .cc source files (not as a CcInfo):

load("@rules_bison//bison:bison.bzl", "bison")

bison(
    name = "hello_parser_srcs",
    src = "hello.y",
)

cc_binary(
    name = "hello",
    srcs = [":hello_parser_srcs"],
)

Running Bison in a genrule:

genrule(
    name = "hello_gen",
    srcs = ["hello.y"],
    outs = ["hello_gen.c"],
    cmd = "M4=$(M4) $(BISON) --output=$@ $<",
    toolchains = [
        "@rules_bison//bison:current_bison_toolchain",
        "@rules_m4//m4:current_m4_toolchain",
    ],
)

Writing a custom rule that depends on Bison as a toolchain:

load("@rules_bison//bison:bison.bzl", "BISON_TOOLCHAIN_TYPE", "bison_toolchain")
load("@rules_m4//m4:m4.bzl", "M4_TOOLCHAIN_TYPE")

def _my_rule(ctx):
    bison = bison_toolchain(ctx)
    ctx.actions.run(
        executable = bison.bison_tool,
        env = bison.bison_env,
        # ...
    )

my_rule = rule(
    implementation = _my_rule,
    toolchains = [
        BISON_TOOLCHAIN_TYPE,
        M4_TOOLCHAIN_TYPE,
    ],
)