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Merge topic 'doc-if-dereferencing-issue-10773' 

7d9b903 Clarify auto-dereference cases in if() command (#11701)
e4e14e8 Replace misleading example in the if() documentation (#10773)
This commit is contained in:
Brad King 2011-01-19 14:02:26 -05:00 committed by CMake Topic Stage
parent c6cb693147 7d9b903756
commit db276e48c4
1 changed files with 37 additions and 52 deletions
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87
Source/cmIfCommand.h
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@ -126,9 +126,12 @@ public:
"False if the constant is 0, OFF, NO, FALSE, N, IGNORE, \"\", "
"or ends in the suffix '-NOTFOUND'. "
"Named boolean constants are case-insensitive. "
"If the argument is not one of these constants, "
"it is treated as a variable:"
"\n"
" if(<variable>)\n"
"True if the variable's value is not a false constant."
"True if the variable is defined to a value that is not a false "
"constant. False otherwise. "
"\n"
" if(NOT <expression>)\n"
"True if the expression is not true."
@ -163,32 +166,25 @@ public:
"Behavior is well-defined only for full paths.\n"
" if(IS_ABSOLUTE path)\n"
"True if the given path is an absolute path.\n"
" if(variable MATCHES regex)\n"
" if(string MATCHES regex)\n"
" if(<variable|string> MATCHES regex)\n"
"True if the given string or variable's value matches the given "
"regular expression.\n"
" if(variable LESS number)\n"
" if(string LESS number)\n"
" if(variable GREATER number)\n"
" if(string GREATER number)\n"
" if(variable EQUAL number)\n"
" if(string EQUAL number)\n"
" if(<variable|string> LESS <variable|string>)\n"
" if(<variable|string> GREATER <variable|string>)\n"
" if(<variable|string> EQUAL <variable|string>)\n"
"True if the given string or variable's value is a valid number and "
"the inequality or equality is true.\n"
" if(variable STRLESS string)\n"
" if(string STRLESS string)\n"
" if(variable STRGREATER string)\n"
" if(string STRGREATER string)\n"
" if(variable STREQUAL string)\n"
" if(string STREQUAL string)\n"
" if(<variable|string> STRLESS <variable|string>)\n"
" if(<variable|string> STRGREATER <variable|string>)\n"
" if(<variable|string> STREQUAL <variable|string>)\n"
"True if the given string or variable's value is lexicographically "
"less (or greater, or equal) than the string or variable on the right.\n"
" if(version1 VERSION_LESS version2)\n"
" if(version1 VERSION_EQUAL version2)\n"
" if(version1 VERSION_GREATER version2)\n"
" if(<variable|string> VERSION_LESS <variable|string>)\n"
" if(<variable|string> VERSION_EQUAL <variable|string>)\n"
" if(<variable|string> VERSION_GREATER <variable|string>)\n"
"Component-wise integer version number comparison (version format is "
"major[.minor[.patch[.tweak]]]).\n"
" if(DEFINED variable)\n"
" if(DEFINED <variable>)\n"
"True if the given variable is defined. It does not matter if the "
"variable is true or false just if it has been set.\n"
" if((expression) AND (expression OR (expression)))\n"
@ -199,38 +195,27 @@ public:
"that contains them."
"\n"
"The if statement was written fairly early in CMake's history "
"and it has some convenience features that are worth covering. "
"The if statement reduces operations until there is "
"a single remaining value, at that point if the case "
"insensitive value is: ON, 1, YES, TRUE, Y it returns true, if "
"it is OFF, 0, NO, FALSE, N, NOTFOUND, *-NOTFOUND, IGNORE it "
"will return false. \n"
"This is fairly reasonable. The convenience feature that sometimes "
"throws new authors is how CMake handles values that do not "
"match the true or false list. Those values are treated as "
"variables and are dereferenced even though they do not have "
"the required ${} syntax. This means that if you write\n"
" if (boobah)\n"
"CMake will treat it as if you wrote \n"
" if (${boobah})\n"
"likewise if you write \n"
" if (fubar AND sol)\n"
"CMake will conveniently treat it as \n"
" if (\"${fubar}\" AND \"${sol}\")\n"
"The later is really the correct way to write it, but the "
"former will work as well. Only some operations in the if "
"statement have this special handling of arguments. The "
"specific details follow: \n"
"The if command was written very early in CMake's history, predating "
"the ${} variable evaluation syntax, and for convenience evaluates "
"variables named by its arguments as shown in the above signatures. "
"Note that normal variable evaluation with ${} applies before the "
"if command even receives the arguments. "
"Therefore code like\n"
" set(var1 OFF)\n"
" set(var2 \"var1\")\n"
" if(${var2})\n"
"appears to the if command as\n"
" if(var1)\n"
"and is evaluated according to the if(<variable>) case "
"documented above. "
"The result is OFF which is false. "
"However, if we remove the ${} from the example then the command sees\n"
" if(var2)\n"
"which is true because var2 is defined to \"var1\" which is not "
"a false constant."
"\n"
"Automatic evaluation applies in the other cases whenever the "
"above-documented signature accepts <variable|string>:\n"
"1) The left hand argument to MATCHES is first checked to see "
"if it is a defined variable, if so the variable's value is "