Commit Graph

127 Commits

Author SHA1 Message Date
Stephen Kelly 0d8db250ce Use a preprocessor loop to manage the valid transitive properties.
Hopefully this will prevent regressions when adding further transitive
properties in the future.
2013-06-10 16:13:21 +02:00
Brad King d3c8688ecd Merge topic 'fix-genex-HEAD-target'
5b22235 Genex: Fix the HEAD target used for evaluated expressions
2013-06-05 09:54:20 -04:00
Stephen Kelly 5b222354de Genex: Fix the HEAD target used for evaluated expressions
If the expression $<TARGET_PROPERTY:prop> appears in the content
of a target property, the target that prop is read from is
the 'head target' of the expression. In contexts such as evaluating
the content of a target property during generation, such
as INCLUDE_DIRECTORIES, the 'head target' is the one on which the
initial request was made.

If evaluating a generator expression which is not a target property
content, the target must be explicitly specified. Such contexts
include add_custom_command and file(GENERATE). The content might
then look like

 $<TARGET_PROPERTY:tgt,prop>

However, as there is no HeadTarget set, any generator expressions
evaluated as part of reading prop from tgt which do not specify
the tgt directly report an error.

Modify the logic of the TARGET_PROPERTY generator expression so
that in such contexts, the 'head target' is set to the appropriate
target which was first encountered.
2013-06-05 09:05:00 -04:00
Stephen Kelly 80ca9c4b41 Add COMPILE_OPTIONS target property.
This method reads generator expressions from the COMPILE_OPTIONS
target property, as well as INTERFACE_COMPILE_OPTIONS from linked
dependents.
2013-06-02 11:56:37 +02:00
Stephen Kelly 1319a147bd Add <LANG>_COMPILER_ID generator expressions.
These expressions evaluate to the id of the compiler used to build
the target, or can be used to test if the compiler id matches a
specified value.
2013-06-02 11:56:36 +02:00
Brad King 7b8a4c3e6f Merge topic 'fix-INCLUDE_DIRECTORIES-genex-read'
3aa9ce4 GenexEval: Fix evaluation of INCLUDE_DIRECTORIES target property.
0b39fef GenexEval: Extract a getLinkedTargetsContent from TargetPropertyNode.
53164ac cmTarget: Remove some hardcoding of transitive property names.
2013-05-31 09:33:22 -04:00
Stephen Kelly 3aa9ce441f GenexEval: Fix evaluation of INCLUDE_DIRECTORIES target property.
This property should come from the content of the property itself,
plus the INTERFACE_INCLUDE_DIRECTORIES of the link *implementation*.

In contrast, when the INTERFACE_INCLUDE_DIRECTORIES is evaluated for
a target, the INTERFACE_INCLUDE_DIRECTORIES of the link *interface*
is used.

Similar logic applies for the COMPILE_DEFINITIONS target properties.

If the propertyName is already an INTERFACE_ variant of the property,
ie, the expression is similar to

 $<TARGET_PROPERTY:foo,INTERFACE_INCLUDE_DIRECTORIES>

then the INTERFACE_INCLUDE_DIRECTORIES of the link *interface* of foo
is used.

However, if the propertyName is not an INTERFACE_ variant, and the
interfacePropertyName is, ie, the expression is similar to:

 $<TARGET_PROPERTY:foo,INCLUDE_DIRECTORIES>

then the INTERFACE_INCLUDE_DIRECTORIES of the link *implementation*
of foo is used.
2013-05-30 15:43:42 +02:00
Stephen Kelly 0b39fefeac GenexEval: Extract a getLinkedTargetsContent from TargetPropertyNode.
This will be used to process transitive components of properties
which depend on linked targets. Currently only the link interface
of the target can be used as the source of the linked targets, but
in the next commit it will be possible to use the link implementation
as the source of link targets.

This commit does not change the semantics of the code.
2013-05-30 15:43:42 +02:00
Stephen Kelly 53164ac997 cmTarget: Remove some hardcoding of transitive property names. 2013-05-30 15:43:37 +02:00
Brad King 14d90d81de Merge topic 'language-generator-expressions'
3241014 Add $<LINK_LANGUAGE> generator expression
2013-05-24 09:19:15 -04:00
Stephen Kelly 32410140a7 Add $<LINK_LANGUAGE> generator expression
They can't be used when evaluating link libraries, but they can be
used for include directories and compile definitions. Later they can
be used for compile options.
2013-05-24 09:06:53 -04:00
Brad King 3db29d2724 Merge topic 'join-genex'
a7ba452 Add the JOIN generator expression.
96ec314 Make it possible for any genex to have arbitrary content at the end.
bd638ee Rename the method determining if a genex accepts arbitrary content.
dc742fe Extract the ProcessArbitraryContent method.
2013-05-22 13:35:15 -04:00
Brad King d2cd362c31 Merge topic 'fix-genex-comma-parse'
05bf972 Fix handling of commas in arbitrary content in genexes.
2013-05-21 15:19:26 -04:00
Stephen Kelly 44258cc26c Remove unused typedef. 2013-05-17 09:01:01 +02:00
Stephen Kelly a7ba4520c7 Add the JOIN generator expression.
This generator expression joins a list with a separator. The separator
may contain arbitrary content, such as commas, which is ordinarily a
delimiter in the generator expression syntax.
2013-05-16 19:36:31 +02:00
Stephen Kelly 96ec3147bb Make it possible for any genex to have arbitrary content at the end. 2013-05-16 19:36:31 +02:00
Stephen Kelly bd638ee20f Rename the method determining if a genex accepts arbitrary content.
The meaning of this will be expanded to generator expressions with
more than a single parameter.
2013-05-16 19:36:31 +02:00
Stephen Kelly dc742fe4be Extract the ProcessArbitraryContent method. 2013-05-16 19:36:31 +02:00
Stephen Kelly 05bf9721e4 Fix handling of commas in arbitrary content in genexes.
As the comma is the parameter separator, it needs to be re-added
when evaluating to reconstruct arbitrary content.
2013-05-16 19:25:06 +02:00
Jean-Christophe Fillion-Robin 7f3bb8b392 Add $<SEMICOLON> generator expression.
This expression is useful to put a ';' in a command line argument
without dividing the argument during CMake list expansion.
2013-03-12 16:46:03 -04:00
Brad King b4bb074d8b Merge topic 'remove-TARGET_DEFINED-genex'
cbf0756 Revert "Add the TARGET_DEFINED generator expression"
21a342c Remove use of TARGET_DEFINED from the target_link_libraries test.
47b8d32 Remove use of TARGET_DEFINED from the ExportImport test.
2e39d21 Remove use of TARGET_DEFINED from target_include_directories test.
2013-03-04 15:39:45 -05:00
Brad King 57072c12d2 Merge topic 'interface-property-external-read'
8dfdf1c Fix the tests for evaluating includes and defines.
98a6725 Fix constness of accessors.
7e70744 Expand includes and defines transitively in 'external' genexes.
d1a2729 Fix DAG checker finding cycling dependencies.
e72eaad Workaround broken code where a target has itself in its link iface.
ec2c67b Strip stray semicolons when evaluating generator expressions.
2013-02-25 13:12:12 -05:00
Stephen Kelly cbf07569ed Revert "Add the TARGET_DEFINED generator expression"
This reverts commit 2bee6f5ba5.

This expression is not used, and has a semantic which is not completely
optimal (namely considering utility targets to be targets, though
usually we are interested in linkable targets).

Remove it so that we have more freedom to define better expressions in
the future.

Conflicts:
        Source/cmGeneratorExpressionEvaluator.cxx
        Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt
        Tests/CMakeCommands/target_compile_definitions/consumer.cpp
2013-02-25 15:35:11 +01:00
Stephen Kelly 7e707444be Expand includes and defines transitively in 'external' genexes.
This means that we can use expressions of the form

 $<TARGET_PROPERTY:foo,INTERFACE_INCLUDE_DIRECTORIES>

to get a list of the interface include directories of foo, including
those coming from dependencies.

We can't have a test of a target which has a single include directory in
its INCLUDE_DIRECTORIES because the shell on the MSYS platforms transforms
a single include directory to include a prefix, which is not what the test
expects. We test a target with two directories instead as a means to
test a target with no link dependencies.
2013-02-23 09:42:24 +01:00
Stephen Kelly e72eaadc42 Workaround broken code where a target has itself in its link iface.
There is a test for this since commit 8e756d2b (Tolerate cycles in
shared library link interfaces (#12647), 2012-01-12), so make sure
it continues to pass, even as we require no self-references in new
INTERFACE_ property generator expressions.
2013-02-23 09:41:22 +01:00
Stephen Kelly f2ab17d4db Keep track of all targets seen while evaluating a genex.
As dependencies of the generator expression, these will re-exported
in try_compile generated code.
2013-02-22 08:35:29 -05:00
Stephen Kelly ec2c67bcf3 Strip stray semicolons when evaluating generator expressions. 2013-02-18 12:07:32 +01:00
Stephen Kelly 3df36b5954 Revert "Add the $<LINKED:...> generator expression."
This reverts commit 0b92602b81.

Conflicts:
	Source/cmGeneratorExpressionEvaluator.cxx
	Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt
	Tests/CMakeCommands/target_include_directories/CMakeLists.txt
2013-02-13 15:12:31 +01:00
Stephen Kelly 567c8d103e Revert "Don't allow utility or global targets in the LINKED expression."
This reverts commit 9712362b45.
2013-02-13 15:12:31 +01:00
Stephen Kelly a1c4905f72 Use the link information as a source of compile definitions and includes.
After evaluating the INTERFACE_INCLUDE_DIRECTORIES, of a target in a
generator expression, also read the INTERFACE_INCLUDE_DIRECTORIES of
its link interface dependencies.

That means that code such as this will result in the 'user' target
using /bar/include and /foo/include:

 add_library(foo ...)
 target_include_directories(foo INTERFACE /foo/include)
 add_library(bar ...)
 target_include_directories(bar INTERFACE /bar/include)
 target_link_libraries(bar LINK_PUBLIC foo)

 add_executable(user ...)
 target_include_directories(user PRIVATE
    $<TARGET_PROPERTY:bar,INTERFACE_INCLUDE_DIRECTORIES>)

Also process the interface include directories from direct link
dependencies for in-build targets.

The situation is similar for the INTERFACE_COMPILE_DEFINITIONS. The
include directories related code is currently more complex because
we also need to store a backtrace at configure-time for the purpose
of debugging includes. The compile definitions related code will use
the same pattern in the future.

This is not a change in behavior, as existing code has the same effect,
but that existing code will be removed in follow-up commits.
2013-02-13 15:12:30 +01:00
Stephen Kelly 9712362b45 Don't allow utility or global targets in the LINKED expression.
The LINKED expression is exclusively for handling INTERFACE content
and it does not make sense for utility targets to have INTERFACE
content.
2013-02-08 21:44:11 +01:00
Stephen Kelly d4e5c6787c Don't keep track of content determined by target property values.
This tracking was added during the development of commit 042ecf04
(Add API to calculate link-interface-dependent bool properties
or error., 2013-01-06), but was never used.

It was not necessary to use the content because what is really
useful in that logic is to determine if a property has been implied
to be null by appearing in a LINK_LIBRARIES genex.

I think the motivating usecase for developing the feature of
keeping track of the targets relevant to a property was that I
thought it would  make it possible to allow requiring granular
compatibility of interface properties only for targets which
depended on the interface property. Eg:

 add_library(foo ...)
 add_library(bar ...)

 add_executable(user ...)
 # Read the INTERFACE_POSITION_INDEPENDENT_CODE from bar, but not
 # from foo:
 target_link_libraries(user foo $<$<TARGET_PROPERTY:POSTITION_INDEPENDENT_CODE>:bar>)

This obviously doesn't make sense. We require that INTERFACE
properties are consistent across all linked targets instead.
2013-02-07 16:21:09 +01:00
Stephen Kelly 1fb545ad3a Move a special case for PIC from the genex to the cmTarget code. 2013-02-07 16:21:09 +01:00
Stephen Kelly 57175d559e Only use early evaluation termination for transitive properties.
We need to make sure expressions which evaluate TARGET_PROPERTY:TYPE
multiple times for example get the correct result each time, and
not an empty string instead.
2013-02-07 16:21:09 +01:00
Stephen Kelly 7c0ec75cfa De-duplicate validation of genex target names. 2013-02-07 16:21:08 +01:00
Stephen Kelly e48d84209c Cache context-independent includes on evaluation.
Generator expressions whose output depends on the configuration
now record that fact. The GetIncludeDirectories method can use
that result to cache the include directories for later calls.

GetIncludeDirectories is called multiple times for a target
for each configuration, so this should restore performance for
multi-config generators.
2013-02-03 23:04:03 +01:00
Stephen Kelly 089fe1c13d Optimize genex evaluation for includes and defines.
While porting boost to use these features, the generation step took
too long (several minutes before I stopped it). The reason was that
the boost libraries form a large interdependent mesh. The libraries
list their dependencies in their INTERFACE such as:

 $<LINKED:boost::core>;$<LINKED:boost::config>;$<LINKED:boost::mpl>

As boost::core already depends on the boost::config libraries, that
expression has no impact on the end-content, as it is removed after
the generation step. There is no DAG issue though, so the generator
expression evaluation would fully evaluate them. In the case of the
config library, it also depends on the core library, so all depends
are followed through that again, despite the fact that they've just
been evaluated. After this patch, the evaluation skips libraries if
they have already been seen via depends or directly in the content.

This patch keeps track of targets whose INTERFACE has been consumed
already. The INCLUDE_DIRECTORIES and COMPILE_DEFINITIONS properties
are whitelisted because repeated content will be stripped out later
during generation. For other properties now and in the future, that
may not be the case.
2013-02-02 15:06:53 +01:00
Stephen Kelly 0b92602b81 Add the $<LINKED:...> generator expression.
This is both a short form of using a TARGET_DEFINED expression
together with a TARGET_PROPERTY definition, and a way to strip
non-target content from interface properties when exporting.
2013-01-31 17:34:20 +01:00
Stephen Kelly df4d2b28b2 Make it an error for INSTALL_PREFIX to be evaluated.
An empty string is not likely going to produce expected results
in any evaluation context. It is replaced by preprocessing
currently.
2013-01-31 17:27:06 +01:00
Stephen Kelly 30268b46f8 Handle reading empty properties defined by the link interface.
This was segfaulting before.
2013-01-31 11:18:49 +01:00
Stephen Kelly 34d1ade048 Add the INSTALL_PREFIX genex. 2013-01-27 09:59:26 +01:00
Stephen Kelly 2fb2c32f9b Add the COMPATIBLE_INTERFACE_STRING property. 2013-01-24 20:36:04 +01:00
Brad King a37b0e3ebf Merge topic 'qt4-autolink-qtmain'
e3b5eb6 Automatically link to the qtmain library when linking to QtCore.
6c8d8af Add the $<TARGET_POLICY> expression
2013-01-23 15:11:24 -05:00
Stephen Kelly e3b5eb6b23 Automatically link to the qtmain library when linking to QtCore.
When using QAxServer, ensure that the qtmain library is excluded
by reporting an error at CMake time if it is not.
2013-01-23 14:15:41 -05:00
Stephen Kelly e98799105b Make INTERFACE determined properties readable in generator expressions.
The properties are evaluated as link-dependent interface properties when
evaluating the generator expressions.
2013-01-20 17:06:47 +01:00
Stephen Kelly 6c8d8afe34 Add the $<TARGET_POLICY> expression
This new expression allows checking how a policy was set when a target
was created.  That information is only recorded for a subset of policies,
so a whitelist is used.
2013-01-17 17:20:17 +01:00
Stephen Kelly 2bee6f5ba5 Add the TARGET_DEFINED generator expression
This tests whether the parameter is a usable target.
2013-01-14 00:08:47 +01:00
Stephen Kelly bf5ece51c3 Keep track of properties used to determine linker libraries.
Those properties can't later be implicitly defined by the interface
of those link libraries.
2013-01-08 20:38:16 +01:00
Brad King db925e3532 Merge topic 'interface-includes-defines'
894f52f Handle INTERFACE properties transitively for includes and defines.
f5b1980 Populate the ExportedTargets member early in GenerateMainFile
c67b812 Make cycles in target properties ignored, not an error.
d0f950f Use mapped config properties to evaluate $<CONFIG>
26def17 Make all relevant targets available in the genex context.
0c657dc Add API to populate INTERFACE properties in exported targets.
e04f737 Add API to extract target names from a genex string.
b0c8f73 Add the TARGET_NAME generator expression.
77475fe Allow generator expressions to require literals.
b2f1700 GenEx: Add expressions to specify build- or install-only values
2013-01-07 14:20:13 -05:00
Stephen Kelly 894f52f32d Handle INTERFACE properties transitively for includes and defines.
Contextually, the behavior is as if the properties content from another
target is included in the string and then the result is evaluated.
2013-01-05 01:18:37 +01:00
Stephen Kelly c67b8124f7 Make cycles in target properties ignored, not an error.
Constructs such as these are an error as they are direct self-references:

 set_property(TARGET foo APPEND PROPERTY
   INCLUDE_DIRECTORIES $<TARGET_PROPERTY:foo,INCLUDE_DIRECTORIES>)
 set_property(TARGET foo APPEND PROPERTY
   INCLUDE_DIRECTORIES $<TARGET_PROPERTY:INCLUDE_DIRECTORIES>)

However, this is an indirect self-reference in a cycle, and not an error:

 set_property(TARGET foo APPEND PROPERTY
   INCLUDE_DIRECTORIES $<TARGET_PROPERTY:bar,INCLUDE_DIRECTORIES>)
 set_property(TARGET bar APPEND PROPERTY
   INCLUDE_DIRECTORIES $<TARGET_PROPERTY:foo,INCLUDE_DIRECTORIES>)
2013-01-05 01:18:36 +01:00
Stephen Kelly d0f950fdba Use mapped config properties to evaluate $<CONFIG> 2013-01-05 01:18:36 +01:00
Stephen Kelly 26def1771d Make all relevant targets available in the genex context.
The current node being evaluated transitively in the generator
expression must be available to resolve mapped configs.
2013-01-05 01:18:36 +01:00
Stephen Kelly b0c8f73eb6 Add the TARGET_NAME generator expression.
It will be used as a preprocessing marker.
2013-01-05 01:05:09 +01:00
Stephen Kelly 77475fe61d Allow generator expressions to require literals. 2013-01-05 01:05:09 +01:00
Stephen Kelly b2f1700bc7 GenEx: Add expressions to specify build- or install-only values
This is for specifying INCLUDE_DIRECTORIES relevant to the build-location
or the install location for example:

 set_property(TARGET foo PROPERTY
   INTERFACE_INCLUDE_DIRECTORIES
   "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR};${CMAKE_CURRENT_SOURCE_DIR}>"
   "$<INSTALL_INTERFACE:${CMAKE_INSTALL_PREFIX}/include>"
 )

A 'bar' target can then use:

 set_property(TARGET bar PROPERTY
   INCLUDE_DIRECTORIES
   "$<TARGET_PROPERTY:foo,INTERFACE_INCLUDE_DIRECTORIES>"
 )

and it will work whether foo is in the same project, or an imported target
from an installation location, or an imported target from a build location
generated by the export() command.

Because the generator expressions are only evaluated at build-time, these
new expressions are equivalent to the ZeroNode and OneNode.

The GeneratorExpression test is split into parts. Some shells can't run
the custom command as it is getting too long.
2013-01-05 01:05:08 +01:00
Stephen Kelly e767ffcda5 Don't crash when a target is expected but is not available. 2013-01-03 20:56:32 +01:00
Stephen Kelly 7d736af60e Replace some 'if' with 'else if'
For consistency with the rest of the method.
2012-12-23 16:37:01 +01:00
Brad King 5f30a56f29 Merge topic 'generator-expression-fixes'
b581be0 Genex: Don't segfault on $<FOO,>
07749e3 Genex: Ensure that $<0:...> has a parameter.
ee96dc7 Genex: Extract a method to parse parameters.
2012-11-27 13:35:02 -05:00
Stephen Kelly 07749e3705 Genex: Ensure that $<0:...> has a parameter. 2012-11-27 09:12:39 -05:00
Stephen Kelly ee96dc7686 Genex: Extract a method to parse parameters. 2012-11-26 22:52:22 +01:00
Stephen Kelly d8a59ea4b3 Port cmGeneratorExpression to cmTarget from cmGeneratorTarget.
Following from the discussion here:

 http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/3615/focus=5170
 (Re: Generator expressisons in target properties, 26 Oct 12:10)

we can't split cmTarget API for linking into cmGeneratorTarget. In
the future we will probably also need to move the include and compile
definitions API back to cmTarget so that it can be used by export().
2012-11-21 00:11:54 +01:00
Stephen Kelly 9be64f34c2 GenEx: Use case insensitive comparison for $<CONFIG:...>
This fixes a regression introduced by commit f1eacf0e
(cmGeneratorExpression: Re-write for multi-stage evaluation).
2012-11-05 08:49:25 -05:00
Stephen Kelly e386992152 GexEx: Validate Target names and property names differently.
In the unit test, use the same IMPORTED_LOCATION trick that
the ExportImport test uses.
2012-10-22 14:05:48 -04:00
Stephen Kelly a573a85658 Attempt to fix the compile of cmake on Sun CC.
The problem may be that the reportError method is static, so make
it non-static on that platform.
2012-10-11 22:31:35 +02:00
Stephen Kelly 7aa99270fa GenEx: Don't use std::vector::at(int).
It might not exist with GCC 2.9.
2012-10-09 08:26:56 -04:00
Stephen Kelly 354face4fa GenEx: Ensure that the empty CONFIGURATION can be used conditionally.
The CONFIGURATION can not be manipulated at unit testing time, so
this is not unit tested further.
2012-10-09 08:26:48 -04:00
Stephen Kelly 8b3b88abd8 GenEx: Validate target and property names.
They must be non-empty, and match a restrictive regexp.
2012-10-09 08:26:45 -04:00
Stephen Kelly a4985a9af9 GenEx: Report actual target name not found, not "0" each time. 2012-10-09 08:26:40 -04:00
Stephen Kelly d70650d6c3 GenEx: Return after error reported. 2012-10-09 08:26:37 -04:00
Brad King 103d99338a Merge topic 'generator-expression-target-properties'
083de7e Process generator expressions in the COMPILE_DEFINITIONS target property.
08cb4fa Process generator expressions in the INCLUDE_DIRECTORIES property.
0ef091d Early return if there is no target.
eb250cd Add a self-reference check for target properties.
7e80747 Add API to check that dependent target properties form a DAG.
239ac84 Add a generator expression for target properties.
e028381 Extend the generator expression language with more logic.
b8e61d6 Refactor GetCompileDefinitions a bit.
2c2b25b Return a std::string from GetCompileDefinitions.
b7e48e0 Add an AppendDefines std::string overload.
9a16087 Convert paths in INCLUDE_DIRECTORIES property to Unix slashes.
4557c8d Don't prepend a path before generator expressions in include_directories.
c6abc41 Add include guard for cmGeneratorExpression.
0ff4e3f Port remaining code to GetCompileDefinitions().
f178d53 Fix indentation in the code blocks generator.
2012-09-28 17:15:03 -04:00
Stephen Kelly eb250cd18a Add a self-reference check for target properties.
Prevent constructs like:

 ... INCLUDE_DIRECTORIES "$<TARGET_PROPERTY:INCLUDE_DIRECTORIES>"

Indirect self-references (cycles) are also prevented here, but
indirect generator expression references of any kind are not
possible yet anyway.
2012-09-28 08:49:21 -04:00
Stephen Kelly 7e807472d2 Add API to check that dependent target properties form a DAG.
Initially this will only be used to check for self-references, but
can be extended to check for cycles when chaining properties of other
targets.
2012-09-28 08:49:21 -04:00
Stephen Kelly 239ac84153 Add a generator expression for target properties.
There are two overloads, so that it can use the operational
target when a target property is being evaluated, and a target
can alternatively be specified by name.

At this point, the generators don't chain. That comes later.
2012-09-28 08:49:21 -04:00
Stephen Kelly e028381bf1 Extend the generator expression language with more logic.
Generator expressions for comparing strings, evaluating
strings as booleans, and for creating literal right-angle-brackets
and commas are added. Those may be needed in some cases
where they appear in literals.
2012-09-28 08:49:21 -04:00
Stephen Kelly fb578c8635 Fix the regular expression validator for target names.
Regression introduced by f1eacf0e07.
Target names have different valid contents to config names.
2012-09-20 12:13:33 +02:00
Stephen Kelly f1eacf0e07 cmGeneratorExpression: Re-write for multi-stage evaluation
The expressions may be parsed and then cached and evaluated multiple
times.  They are evaluated lazily so that literals such as ',' can be
treated as universal parameter separators, and can be processed from
results without appearing literally, and without interfering with the
parsing/evaluation of the entire expression.
2012-09-18 17:02:23 -04:00