Cmake - Autom. regenerate a file using an external tool and custom target upon "make"

Hi. I'm working on a project and I use cmake for generating "projects", that is, under Linux, a Makefile.

I also use an external tool (re2c) to generate the scanner, and an included tool to generate the parser (lemon, part of sqlite).

The problem is I need to "cmake" every time I change something in the grammar (lemon_parser.y) or in the scanner (scanner.re).
I'd rather need them be regenerated by make itself.

The cmake files are:
./CMakeLists.txt:

Code:

---

1 cmake_minimum_required(VERSION 2.6)
2 project(Calc C)
3 #set(CMAKE_USE_RELATIVE_PATHS ON FORCE)
4 set(CMAKE_BUILD_TYPE Debug)
5 #set(CMAKE_VERBOSE_MAKEFILE true)
6 include_directories(${CMAKE_SOURCE_DIR} ${CMAKE_BINARY_DIR}/parser)
7
8 IF ( ${CMAKE_SOURCE_DIR} EQUAL ${CMAKE_BINARY_DIR} AND NOT ${ACCEPT_SOURCE_DIR} )
9 MESSAGE( FATAL "Please choose a different directory for building" )
10 ENDIF( ${CMAKE_SOURCE_DIR} EQUAL ${CMAKE_BINARY_DIR} AND NOT ${ACCEPT_SOURCE_DIR} )
11
12 add_subdirectory(lemon)
13 add_subdirectory(hash)
14 add_subdirectory(parser)
15 #memory safety
16 #add_subdirectory(memory_safety)
17
18 add_executable(calc main.c)
19 target_link_libraries(calc hash parser)

---

./parser/CMakeLists.txt

Code:

---

1 set(parser_odir "${CMAKE_CURRENT_BINARY_DIR}/")
2 include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${parser_odir})
3
4 add_custom_command(
5 OUTPUT "${parser_odir}lemon_parser.c" "${parser_odir}lemon_parser.h" "${parser_odir}lemon_parser.out"
6 #COMMAND ${PROJECT_BINARY_DIR}/lemon/lemon d="${CMAKE_CURRENT_SOURCE_DIR}/lempar.c" "${CMAKE_CURRENT_BINARY_DIR}/lemon_parser.y"
7 COMMAND ${PROJECT_BINARY_DIR}/lemon/lemon d="${CMAKE_CURRENT_SOURCE_DIR}/lempar.c" "${parser_odir}lemon_parser.y"
8 DEPENDS lemon "${CMAKE_CURRENT_SOURCE_DIR}/lemon_parser.y"
9 )
10 #add_custom_target(lemon_parser)
11 file(READ lemon_parser.y parser_content)
12 file(WRITE "${parser_odir}lemon_parser.y" "${parser_content}")
13
14 add_custom_command(
15 OUTPUT "${parser_odir}scanner.c"
16 COMMAND re2c -i "${CMAKE_CURRENT_SOURCE_DIR}/scanner.re" > "${parser_odir}scanner.c"
17 DEPENDS "${parser_odir}lemon_parser.h" "${CMAKE_CURRENT_SOURCE_DIR}/scanner.re"
18 )
19 #add_custom_target(re2c_scanner)
20
21 #add_custom_target(lemon_parser ALL DEPENDS "${parser_odir}lemon_parser.c" "${parser_odir}lemon_parser.h")
22 add_library(parser STATIC "${parser_odir}lemon_parser.c" "${parser_odir}scanner.c" parser.c ast.c)

---

and a file irrelevant to the problem:
./hash/CMakeLists.txt:

Code:

---

1 add_library(hash STATIC hash_table.c hash_functions.c)

---

I suppose it's a trivial task for the experienced cmake user.

Thanks in advance.
Cheers.

Solved. The solution was

Code:

---

    1        set(parser_odir "${CMAKE_CURRENT_BINARY_DIR}/")
    2        include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${parser_odir})
    3       
    4        #The right way to me would be to use the commands (2) and (4)
    5        #but it seems one needs (1) and (3) instead, if regeneration
    6        #of the scanner.re and parser.y is desired with only a "make"
    7        #command.
    8        #
    9        #Why I think that would be the right way? Because commands
    10        #have output (in cmake terms) and targets don't.
    11       
    12        add_custom_target(lemon_parser
    13                COMMAND ${CMAKE_COMMAND} -E copy "lemon_parser.y" "${parser_odir}lemon_parser.y"
    14        #(1):
    15                COMMAND ${PROJECT_BINARY_DIR}/lemon/lemon d="${CMAKE_CURRENT_SOURCE_DIR}/lempar.c" "${parser_odir}lemon_parser.y"
    16                WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    17                COMMENT "add_custom_target(lemon_parser)"
    18                )
    19        add_custom_command(OUTPUT "${parser_odir}lemon_parser.c"
    20        #(2):
    21        #        COMMAND ${PROJECT_BINARY_DIR}/lemon/lemon d="${CMAKE_CURRENT_SOURCE_DIR}/lempar.c" "${parser_odir}lemon_parser.y"
    22                COMMENT "add_custom_command(parser)"
    23                )
    24       
    25        add_custom_target(re2c_scanner
    26        #(3):
    27                COMMAND re2c -i "${CMAKE_CURRENT_SOURCE_DIR}/scanner.re" > "${parser_odir}scanner.c"
    28                COMMENT "add_custom_target(re2c_scanner)"
    29                )
    30        add_custom_command(OUTPUT "${parser_odir}scanner.c"
    31        #(4):
    32        #        COMMAND re2c -i "${CMAKE_CURRENT_SOURCE_DIR}/scanner.re" > "${parser_odir}scanner.c"
    33                COMMENT "add_custom_command(scanner)"
    34                )
    35        add_library(parser STATIC parser.c ast.c "${parser_odir}scanner.c" "${parser_odir}lemon_parser.c")
    36        add_dependencies(parser lemon_parser re2c_scanner)
    37        add_dependencies(lemon_parser lemon)

---

Hopefully this will help someone else.