CMake/Modules/FindFLEX.cmake

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CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
FindFLEX
--------
Find flex executable and provides a macro to generate custom build rules
The module defines the following variables:
::
FLEX_FOUND - true is flex executable is found
FLEX_EXECUTABLE - the path to the flex executable
FLEX_VERSION - the version of flex
FLEX_LIBRARIES - The flex libraries
FLEX_INCLUDE_DIRS - The path to the flex headers
The minimum required version of flex can be specified using the
standard syntax, e.g. find_package(FLEX 2.5.13)
If flex is found on the system, the module provides the macro:
::
FLEX_TARGET(Name FlexInput FlexOutput
[COMPILE_FLAGS <string>]
[DEFINES_FILE <string>]
)
which creates a custom command to generate the <FlexOutput> file from
the <FlexInput> file. If COMPILE_FLAGS option is specified, the next
parameter is added to the flex command line. If flex is configured to
output a header file, the DEFINES_FILE option may be used to specify its
name. Name is an alias used to get details of this custom command.
Indeed the macro defines the following variables:
::
FLEX_${Name}_DEFINED - true is the macro ran successfully
FLEX_${Name}_OUTPUTS - the source file generated by the custom rule, an
alias for FlexOutput
FLEX_${Name}_INPUT - the flex source file, an alias for ${FlexInput}
FLEX_${Name}_OUTPUT_HEADER - the header flex output, if any.
Flex scanners often use tokens defined by Bison: the code generated
by Flex depends of the header generated by Bison. This module also
defines a macro:
::
ADD_FLEX_BISON_DEPENDENCY(FlexTarget BisonTarget)
which adds the required dependency between a scanner and a parser
where <FlexTarget> and <BisonTarget> are the first parameters of
respectively FLEX_TARGET and BISON_TARGET macros.
::
====================================================================
Example:
::
find_package(BISON)
find_package(FLEX)
::
BISON_TARGET(MyParser parser.y ${CMAKE_CURRENT_BINARY_DIR}/parser.cpp)
FLEX_TARGET(MyScanner lexer.l ${CMAKE_CURRENT_BINARY_DIR}/lexer.cpp)
ADD_FLEX_BISON_DEPENDENCY(MyScanner MyParser)
::
include_directories(${CMAKE_CURRENT_BINARY_DIR})
add_executable(Foo
Foo.cc
${BISON_MyParser_OUTPUTS}
${FLEX_MyScanner_OUTPUTS}
)
====================================================================
#]=======================================================================]
find_program(FLEX_EXECUTABLE NAMES flex win_flex DOC "path to the flex executable")
mark_as_advanced(FLEX_EXECUTABLE)
find_library(FL_LIBRARY NAMES fl
DOC "Path to the fl library")
find_path(FLEX_INCLUDE_DIR FlexLexer.h
DOC "Path to the flex headers")
mark_as_advanced(FL_LIBRARY FLEX_INCLUDE_DIR)
set(FLEX_INCLUDE_DIRS ${FLEX_INCLUDE_DIR})
set(FLEX_LIBRARIES ${FL_LIBRARY})
if(FLEX_EXECUTABLE)
execute_process(COMMAND ${FLEX_EXECUTABLE} --version
OUTPUT_VARIABLE FLEX_version_output
ERROR_VARIABLE FLEX_version_error
RESULT_VARIABLE FLEX_version_result
OUTPUT_STRIP_TRAILING_WHITESPACE)
if(NOT ${FLEX_version_result} EQUAL 0)
if(FLEX_FIND_REQUIRED)
message(SEND_ERROR "Command \"${FLEX_EXECUTABLE} --version\" failed with output:\n${FLEX_version_output}\n${FLEX_version_error}")
else()
message("Command \"${FLEX_EXECUTABLE} --version\" failed with output:\n${FLEX_version_output}\n${FLEX_version_error}\nFLEX_VERSION will not be available")
endif()
else()
# older versions of flex printed "/full/path/to/executable version X.Y"
# newer versions use "basename(executable) X.Y"
get_filename_component(FLEX_EXE_NAME_WE "${FLEX_EXECUTABLE}" NAME_WE)
get_filename_component(FLEX_EXE_EXT "${FLEX_EXECUTABLE}" EXT)
string(REGEX REPLACE "^.*${FLEX_EXE_NAME_WE}(${FLEX_EXE_EXT})?\"? (version )?([0-9]+[^ ]*)( .*)?$" "\\3"
FLEX_VERSION "${FLEX_version_output}")
unset(FLEX_EXE_EXT)
unset(FLEX_EXE_NAME_WE)
endif()
#============================================================
# FLEX_TARGET (public macro)
#============================================================
#
macro(FLEX_TARGET Name Input Output)
set(FLEX_TARGET_outputs "${Output}")
set(FLEX_EXECUTABLE_opts "")
set(FLEX_TARGET_PARAM_OPTIONS)
set(FLEX_TARGET_PARAM_ONE_VALUE_KEYWORDS
COMPILE_FLAGS
DEFINES_FILE
)
set(FLEX_TARGET_PARAM_MULTI_VALUE_KEYWORDS)
cmake_parse_arguments(
FLEX_TARGET_ARG
"${FLEX_TARGET_PARAM_OPTIONS}"
"${FLEX_TARGET_PARAM_ONE_VALUE_KEYWORDS}"
"${FLEX_TARGET_MULTI_VALUE_KEYWORDS}"
${ARGN}
)
set(FLEX_TARGET_usage "FLEX_TARGET(<Name> <Input> <Output> [COMPILE_FLAGS <string>] [DEFINES_FILE <string>]")
if(NOT "${FLEX_TARGET_ARG_UNPARSED_ARGUMENTS}" STREQUAL "")
message(SEND_ERROR ${FLEX_TARGET_usage})
else()
if(NOT "${FLEX_TARGET_ARG_COMPILE_FLAGS}" STREQUAL "")
set(FLEX_EXECUTABLE_opts "${FLEX_TARGET_ARG_COMPILE_FLAGS}")
separate_arguments(FLEX_EXECUTABLE_opts)
endif()
if(NOT "${FLEX_TARGET_ARG_DEFINES_FILE}" STREQUAL "")
list(APPEND FLEX_TARGET_outputs "${FLEX_TARGET_ARG_DEFINES_FILE}")
list(APPEND FLEX_EXECUTABLE_opts --header-file=${FLEX_TARGET_ARG_DEFINES_FILE})
endif()
add_custom_command(OUTPUT ${FLEX_TARGET_outputs}
COMMAND ${FLEX_EXECUTABLE} ${FLEX_EXECUTABLE_opts} -o${Output} ${Input}
VERBATIM
DEPENDS ${Input}
COMMENT "[FLEX][${Name}] Building scanner with flex ${FLEX_VERSION}"
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
set(FLEX_${Name}_DEFINED TRUE)
set(FLEX_${Name}_OUTPUTS ${Output})
set(FLEX_${Name}_INPUT ${Input})
set(FLEX_${Name}_COMPILE_FLAGS ${FLEX_EXECUTABLE_opts})
if("${FLEX_TARGET_ARG_DEFINES_FILE}" STREQUAL "")
set(FLEX_${Name}_OUTPUT_HEADER "")
else()
set(FLEX_${Name}_OUTPUT_HEADER ${FLEX_TARGET_ARG_DEFINES_FILE})
endif()
endif()
endmacro()
#============================================================
#============================================================
# ADD_FLEX_BISON_DEPENDENCY (public macro)
#============================================================
#
macro(ADD_FLEX_BISON_DEPENDENCY FlexTarget BisonTarget)
if(NOT FLEX_${FlexTarget}_OUTPUTS)
message(SEND_ERROR "Flex target `${FlexTarget}' does not exist.")
endif()
if(NOT BISON_${BisonTarget}_OUTPUT_HEADER)
message(SEND_ERROR "Bison target `${BisonTarget}' does not exist.")
endif()
set_source_files_properties(${FLEX_${FlexTarget}_OUTPUTS}
PROPERTIES OBJECT_DEPENDS ${BISON_${BisonTarget}_OUTPUT_HEADER})
endmacro()
#============================================================
endif()
include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(FLEX REQUIRED_VARS FLEX_EXECUTABLE
VERSION_VAR FLEX_VERSION)