Detect readline library in CMakeLists.txt

src/CMakeLists.txt

@@ -1,7 +1,10 @@
 cmake_minimum_required(VERSION 3.20)
 
+list(INSERT CMAKE_MODULE_PATH 0 "${PROJECT_SOURCE_DIR}/src/cmake")
+
 find_package(FLEX)
 find_package(BISON)
+find_package(readline)
 
 set(CMAKE_CXX_FLAGS "-O3 -Wall -std=c++17 -ansi")
 
@@ -21,6 +24,10 @@ else()
     message(STATUS "Flex not found, so executables won't be generated.")
 endif()
 
+if(NOT READLINE_FOUND)
+    message(STATUS "Readline not found, so executables won't be generated.")
+endif()
+
 # Include dir
 include_directories(/usr/local/include)
 

src/cmake/Findreadline.cmake

@@ -0,0 +1,35 @@
+# Try to find libreadline
+# Once done, this will define
+#
+# READLINE_FOUND        - system has readline
+# READLINE_INCLUDE_DIRS - readline include directories
+# READLINE_LIBRARIES    - libraries need to use readline
+#
+# and the following imported targets
+#
+# READLINE::READLINE
+
+find_path(READLINE_INCLUDE_DIR
+  NAMES readline/readline.h
+  HINTS ${READLINE_ROOT})
+
+find_library(READLINE_LIBRARY
+  NAMES readline
+  HINTS ${READLINE_ROOT}
+  PATH_SUFFIXES ${CMAKE_INSTALL_LIBDIR})
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(readline
+  REQUIRED_VARS READLINE_LIBRARY READLINE_INCLUDE_DIR)
+
+mark_as_advanced(READLINE_FOUND READLINE_LIBRARY READLINE_INCLUDE_DIR)
+
+if (READLINE_FOUND AND NOT TARGET READLINE::READLINE)
+  add_library(READLINE::READLINE UNKNOWN IMPORTED)
+  set_target_properties(READLINE::READLINE PROPERTIES
+    IMPORTED_LOCATION "${READLINE_LIBRARY}"
+    INTERFACE_INCLUDE_DIRECTORIES "${READLINE_INCLUDE_DIR}")
+endif()
+
+set(READLINE_INCLUDE_DIRS ${READLINE_INCLUDE_DIR})
+set(READLINE_LIBRARIES ${READLINE_LIBRARY})