在CMake中加入列表的最佳/最短方法 [英] Best/Shortest way to join a list in CMake

问题描述

在CMake中将列表加入字符串的最佳方法是什么?

What is the best way to join a list in CMake into a string?

通过加入，我的意思是将SET(somelist"a""b""c \; c")转换为"a:b:c; c"，其中可以选择粘合字符串(:").以下代码有效，但是它真的很长，有没有更好的方法?

By joining I mean convert SET(somelist "a" "b" "c\;c") to "a:b:c;c" where the glue string (":") is choosable. The following code works but it is REALLY long, is there a better way?

FUNCTION(JOIN LISTNAME GLUE OUTPUT)
SET(_TMP_STR "")
  FOREACH(VAL ${${LISTNAME}})
    SET(_TMP_STR "${_TMP_STR}${GLUE}${VAL}")
  ENDFOREACH(VAL ${${LISTNAME}})
  STRING(LENGTH "${GLUE}" GLUE_LEN)
  STRING(LENGTH "${_TMP_STR}" OUT_LEN)
  MATH(EXPR OUT_LEN ${OUT_LEN}-${GLUE_LEN})
  STRING(SUBSTRING "${_TMP_STR}" ${GLUE_LEN} ${OUT_LEN} _TMP_STR) 
  SET(${OUTPUT} "${_TMP_STR}" PARENT_SCOPE)
ENDFUNCTION()

#USAGE:
SET(somelist "a" "b" "c\;c")
JOIN(somelist ":" output)
MESSAGE("${output}") # will output "a:b:c;c"

不幸的是，使用STRING(REPLACE ...)无效:

Unfortunately using STRING(REPLACE ...) does not work:

function(JOINSTRREPLACE VALUES GLUE OUTPUT)
  string (REPLACE ";" "${GLUE}" _TMP_STR "${VALUES}")
  set (${OUTPUT} "${_TMP_STR}" PARENT_SCOPE)
endfunction()
JOINSTRREPLACE("${somelist}" ":" output)
MESSAGE(${output}) # will output "a:b:c\:c"

推荐答案

通常，此任务通过简单的string REPLACE命令解决.在cmake随附的脚本中可以找到许多这样的替换.但是，如果您真的需要关心值中的分号，则可以使用以下代码:

Usually this task is solved with simple string REPLACE command. You can find a number of such replaces in scripts coming with cmake. But if you really need to care about semicolons inside you values, then you can use the following code:

function(JOIN VALUES GLUE OUTPUT)
  string (REGEX REPLACE "([^\\]|^);" "\\1${GLUE}" _TMP_STR "${VALUES}")
  string (REGEX REPLACE "[\\](.)" "\\1" _TMP_STR "${_TMP_STR}") #fixes escaping
  set (${OUTPUT} "${_TMP_STR}" PARENT_SCOPE)
endfunction()

SET( letters "" "\;a" b c "d\;d" )
JOIN("${letters}" ":" output)
MESSAGE("${output}") # :;a:b:c:d;d

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