CMake/Source/cmIfCommand.h
Brad King cb185d93d2 Fix if() command and CMP0012 OLD/NEW behavior
The commit "modified the if command to address bug 9123 some" changed
the if() command behavior with respect to named boolean constants.  It
introduced policy CMP0012 to provide compatibility.  However, it also
changed behavior with respect to numbers (like '2') but did not cover
the change with the policy.  Also, the behavior it created for numbers
is confusing ('2' is false).

This commit teaches if() to recognize numbers again, and treats them
like the C language does in terms of boolean conversion.  We also fix
the CMP0012 check to trigger in all cases where the result of boolean
coersion differs from that produced by CMake 2.6.4.
2009-10-27 09:07:39 -04:00

285 lines
11 KiB
C++

/*============================================================================
CMake - Cross Platform Makefile Generator
Copyright 2000-2009 Kitware, Inc., Insight Software Consortium
Distributed under the OSI-approved BSD License (the "License");
see accompanying file Copyright.txt for details.
This software is distributed WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the License for more information.
============================================================================*/
#ifndef cmIfCommand_h
#define cmIfCommand_h
#include "cmCommand.h"
#include "cmFunctionBlocker.h"
/** \class cmIfFunctionBlocker
* \brief subclass of function blocker
*
*
*/
class cmIfFunctionBlocker : public cmFunctionBlocker
{
public:
cmIfFunctionBlocker() {
this->HasRun = false; this->ScopeDepth = 0; }
virtual ~cmIfFunctionBlocker() {}
virtual bool IsFunctionBlocked(const cmListFileFunction& lff,
cmMakefile &mf,
cmExecutionStatus &);
virtual bool ShouldRemove(const cmListFileFunction& lff,
cmMakefile &mf);
std::vector<cmListFileArgument> Args;
std::vector<cmListFileFunction> Functions;
bool IsBlocking;
bool HasRun;
unsigned int ScopeDepth;
};
/** \class cmIfCommand
* \brief starts an if block
*
* cmIfCommand starts an if block
*/
class cmIfCommand : public cmCommand
{
public:
/**
* This is a virtual constructor for the command.
*/
virtual cmCommand* Clone()
{
return new cmIfCommand;
}
/**
* This overrides the default InvokeInitialPass implementation.
* It records the arguments before expansion.
*/
virtual bool InvokeInitialPass(const std::vector<cmListFileArgument>& args,
cmExecutionStatus &);
/**
* This is called when the command is first encountered in
* the CMakeLists.txt file.
*/
virtual bool InitialPass(std::vector<std::string> const&,
cmExecutionStatus &) { return false;};
/**
* The name of the command as specified in CMakeList.txt.
*/
virtual const char* GetName() { return "if";}
/**
* Succinct documentation.
*/
virtual const char* GetTerseDocumentation()
{
return "Conditionally execute a group of commands.";
}
/**
* This determines if the command is invoked when in script mode.
*/
virtual bool IsScriptable() { return true; }
/**
* More documentation.
*/
virtual const char* GetFullDocumentation()
{
return
" if(expression)\n"
" # then section.\n"
" COMMAND1(ARGS ...)\n"
" COMMAND2(ARGS ...)\n"
" ...\n"
" elseif(expression2)\n"
" # elseif section.\n"
" COMMAND1(ARGS ...)\n"
" COMMAND2(ARGS ...)\n"
" ...\n"
" else(expression)\n"
" # else section.\n"
" COMMAND1(ARGS ...)\n"
" COMMAND2(ARGS ...)\n"
" ...\n"
" endif(expression)\n"
"Evaluates the given expression. If the result is true, the commands "
"in the THEN section are invoked. Otherwise, the commands in the "
"else section are invoked. The elseif and else sections are "
"optional. You may have multiple elseif clauses. Note that "
"the expression in the else and endif clause is optional. Long "
"expressions can be used and there is a traditional order of "
"precedence. "
"Parenthetical expressions are evaluated first followed by unary "
"operators such as EXISTS, COMMAND, and DEFINED. "
"Then any EQUAL, LESS, GREATER, STRLESS, STRGREATER, STREQUAL, MATCHES "
"will be evaluated. Then NOT operators and finally AND, OR operators "
"will be evaluated. Possible expressions are:\n"
" if(<constant>)\n"
"True if the constant is 1, ON, YES, TRUE, Y, or a non-zero number. "
"False if the constant is 0, OFF, NO, FALSE, N, IGNORE, \"\", "
"or ends in the suffix '-NOTFOUND'. "
"Named boolean constants are case-insensitive."
"\n"
" if(<variable>)\n"
"True if the variable's value is not a false constant."
"\n"
" if(NOT <expression>)\n"
"True if the expression is not true."
"\n"
" if(<expr1> AND <expr2>)\n"
"True if both expressions would be considered true individually."
"\n"
" if(<expr1> OR <expr2>)\n"
"True if either expression would be considered true individually."
"\n"
" if(COMMAND command-name)\n"
"True if the given name is a command, macro or function that can be "
"invoked.\n"
" if(POLICY policy-id)\n"
"True if the given name is an existing policy "
"(of the form CMP<NNNN>).\n"
" if(TARGET target-name)\n"
"True if the given name is an existing target, built or imported.\n"
" if(EXISTS file-name)\n"
" if(EXISTS directory-name)\n"
"True if the named file or directory exists. "
"Behavior is well-defined only for full paths.\n"
" if(file1 IS_NEWER_THAN file2)\n"
"True if file1 is newer than file2 or if one of the two files "
"doesn't exist. "
"Behavior is well-defined only for full paths.\n"
" if(IS_DIRECTORY directory-name)\n"
"True if the given name is a directory. "
"Behavior is well-defined only for full paths.\n"
" if(IS_SYMLINK file-name)\n"
"True if the given name is a symbolic link. "
"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"
"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"
"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"
"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"
"Component-wise integer version number comparison (version format is "
"major[.minor[.patch[.tweak]]]).\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"
"The expressions inside the parenthesis are evaluated first and "
"then the remaining expression is evaluated as in the previous "
"examples. Where there are nested parenthesis the innermost are "
"evaluated as part of evaluating the expression "
"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"
"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 "
"used, otherwise the original value is used. \n"
"2) If the left hand argument to MATCHES is missing it returns "
"false without error \n"
"3) Both left and right hand arguments to LESS GREATER EQUAL "
"are independently tested to see if they are defined variables, "
"if so their defined values are used otherwise the original "
"value is used. \n"
"4) Both left and right hand arguments to STRLESS STREQUAL "
"STRGREATER are independently tested to see if they are defined "
"variables, if so their defined values are used otherwise the "
"original value is used. \n"
"5) Both left and right hand argumemnts to VERSION_LESS "
"VERSION_EQUAL VERSION_GREATER are independently tested to see "
"if they are defined variables, if so their defined values are "
"used otherwise the original value is used. \n"
"6) The right hand argument to NOT is tested to see if it is a "
"boolean constant, if so the value is used, otherwise it is "
"assumed to be a variable and it is dereferenced. \n"
"7) The left and right hand arguments to AND OR are "
"independently tested to see if they are boolean constants, if "
"so they are used as such, otherwise they are assumed to be "
"variables and are dereferenced. \n"
;
}
// this is a shared function for both If and Else to determine if the
// arguments were valid, and if so, was the response true. If there is
// an error, the errorString will be set.
static bool IsTrue(const std::vector<std::string> &args,
std::string &errorString, cmMakefile *mf,
cmake::MessageType &status);
// Get a definition from the makefile. If it doesn't exist,
// return the original string.
static const char* GetVariableOrString(const char* str,
const cmMakefile* mf);
cmTypeMacro(cmIfCommand, cmCommand);
};
#endif