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rules_flex

Bazel rules for Flex, the Fast Lexical Analyzer.

flex

flex(name, flex_options, src)

Generate C/C++ source code for a Flex lexical analyzer.

This rule exists for special cases where the build needs to perform further modification of the generated .c / .h before compilation. Most users will find the flex_cc_library rule more convenient.

Example

load("@rules_flex//flex:flex.bzl", "flex")

flex(
    name = "hello",
    src = "hello.l",
)

ATTRIBUTES

Name Description Type Mandatory Default
name A unique name for this target. Name required
flex_options Additional options to pass to the flex command.

These will be added to the command args immediately before the source file.		 List of strings optional []
src A Flex source file.

The source's file extension will determine whether Flex operates in C or C++ mode:
  • Inputs with file extension .l generate outputs {name}.c and {name}.h.
  • Inputs with file extension .ll, .l++, .lxx, or .lpp generate output {name}.cc. This is equivalent to invoking Flex as flex++.
The C++ output depends on FlexLexer.h, which is part of the Flex source distribution and may be obtained from the Flex toolchain.		 Label required

flex_cc_library

flex_cc_library(name, deps, flex_options, include_prefix, linkstatic, src, strip_include_prefix)

Generate a C/C++ library for a Flex lexical analyzer.

Example

load("@rules_flex//flex:flex.bzl", "flex_cc_library")

flex_cc_library(
    name = "hello_lib",
    src = "hello.l",
)

cc_binary(
    name = "hello",
    srcs = ["hello_main.c"],
    deps = [":hello_lib"],
)

ATTRIBUTES

Name Description Type Mandatory Default
name A unique name for this target. Name required
deps A list of other C/C++ libraries to depend on. List of labels optional []
flex_options Additional options to pass to the flex command.

These will be added to the command args immediately before the source file.		 List of strings optional []
include_prefix A prefix to add to the path of the generated header.

See cc_library.include_prefix for more details.		 String optional ""
linkstatic Disable creation of a shared library output.

See cc_library.linkstatic for more details.		 Boolean optional False
src A Flex source file.

The source's file extension will determine whether Flex operates in C or C++ mode:
  • Inputs with file extension .l generate outputs {name}.c and {name}.h.
  • Inputs with file extension .ll, .l++, .lxx, or .lpp generate output {name}.cc. This is equivalent to invoking Flex as flex++.
The C++ output depends on FlexLexer.h, which is part of the Flex source distribution and may be obtained from the Flex toolchain.		 Label required
strip_include_prefix A prefix to strip from the path of the generated header.

See cc_library.strip_include_prefix for more details.		 String optional ""

flex_repository

flex_repository(name, extra_copts, repo_mapping, version)

Repository rule for Flex.

The resulting repository will have a //bin:flex executable target.

Example

load("@rules_flex//flex:flex.bzl", "flex_repository")

flex_repository(
    name = "flex_v2.6.4",
    version = "2.6.4",
)

ATTRIBUTES

Name Description Type Mandatory Default
name A unique name for this repository. Name required
extra_copts Additional C compiler options to use when building Flex. List of strings optional []
repo_mapping A dictionary from local repository name to global repository name. This allows controls over workspace dependency resolution for dependencies of this repository.<p>For example, an entry "@foo": "@bar" declares that, for any time this repository depends on @foo (such as a dependency on @foo//some:target, it should actually resolve that dependency within globally-declared @bar (@bar//some:target). Dictionary: String -> String required
version A supported version of Flex. String required

flex_toolchain_repository

flex_toolchain_repository(name, flex_repository, repo_mapping)

Toolchain repository rule for Flex toolchains.

Toolchain repositories add a layer of indirection so that Bazel can resolve toolchains without downloading additional dependencies.

The resulting repository will have the following targets:

  • //bin:flex (an alias into the underlying [flex_repository] (#flex_repository))
  • //:toolchain, which can be registered with Bazel.

Example

load(
    "@rules_flex//flex:flex.bzl",
    "flex_repository",
    "flex_toolchain_repository",
)

flex_repository(
    name = "flex_v2.6.4",
    version = "2.6.4",
)

flex_toolchain_repository(
    name = "flex",
    flex_repository = "@flex_v2.6.4",
)

register_toolchains("@flex//:toolchain")

ATTRIBUTES

Name Description Type Mandatory Default
name A unique name for this repository. Name required
flex_repository The name of a flex_repository. String required
repo_mapping A dictionary from local repository name to global repository name. This allows controls over workspace dependency resolution for dependencies of this repository.<p>For example, an entry "@foo": "@bar" declares that, for any time this repository depends on @foo (such as a dependency on @foo//some:target, it should actually resolve that dependency within globally-declared @bar (@bar//some:target). Dictionary: String -> String required

FlexToolchainInfo

FlexToolchainInfo(all_files, flex_tool, flex_env, flex_lexer_h)

Provider for a Flex toolchain.

FIELDS

Name Description
all_files A depset containing all files comprising this Flex toolchain.
flex_tool A FilesToRunProvider for the flex binary.
flex_env Additional environment variables to set when running flex_tool.
flex_lexer_h A File for the FlexLexer.h header.

flex_register_toolchains

flex_register_toolchains(version, extra_copts)

A helper function for Flex toolchains registration.

This workspace macro will create a flex_repository named flex_v{version} and register it as a Bazel toolchain.

PARAMETERS

Name Description Default Value
version A supported version of Flex. "2.6.4"
extra_copts Additional C compiler options to use when building Flex. []

flex_toolchain

flex_toolchain(ctx)

Returns the current FlexToolchainInfo.

PARAMETERS

Name Description Default Value
ctx A rule context, where the rule has a toolchain dependency on FLEX_TOOLCHAIN_TYPE. none

RETURNS

A FlexToolchainInfo.