REPY_FN_IF_CACHE - Conditional Statements Based on Python Scopes

Macros
#define	REPY_FN_IF_CACHE_INIT(helper_identifier)
	Initializes the helpers for cached Pythonic if statements in the current scope.
#define	REPY_FN_IF_CACHE_STMT(helper_identifier, py_expression)
	Constructs a if statement that uses a cached Python expression executed in the current scope.
#define	REPY_FN_IF_CACHE(helper_identifier, py_expression)
	Initializes the helpers for a cached Pythonic if/else block, and constructs the first if statement, using a cached Python expression executed in the local scope.
#define	REPY_FN_ELIF_CACHE(helper_identifier, py_expression)
	Constructs a else if statement that uses a cached Python expression executed in the current scope.

Detailed Description

Because code string parsing and execution requires contiguous, compilable strings, there is no good way to call back into mod code from within a if/else block within Python code. As an alternative, this section provides an easy and performant way to use the Python scope to govern mod code if/else blocks utilizing REPY_IfStmtHelper.

There are no REPY_FN_IF or REPY_FN_IF_CSTR variations of these macros, as simple REPY_FN_EVAL_BOOL and REPY_FN_EVAL_CSTR_BOOL calls could be used as the conditions of if statements directly. Nevertheless, the term CACHE is included in these macro names to indicate that purpose and behavior; As per the design of REPY_IfStmtHelper, the code strings given to these macros are only parsed once, and the bytecode stored for repeated evaluations.

Macro Definition Documentation

REPY_FN_ELIF_CACHE

#define REPY_FN_ELIF_CACHE	(		helper_identifier,
			py_expression )

Value:

else REPY_FN_IF_CACHE_STMT(helper_identifier, py_expression)

Constructs a else if statement that uses a cached Python expression executed in the current scope.

Requires using the helpers initialized by REPY_FN_IF_CACHE_INIT or REPY_FN_IF_CACHE.

See the REPY_IfStmtHelper section for more information.

Parameters

helper_identifier	The variable name of the REPY_IfStmtHelper object. Needs to be the same as the value used when initializing this if/else block (using either REPY_FN_IF_CACHE_INIT or REPY_FN_IF_CACHE).
py_expression	The Python expression to evaluate within the scope. Should be a NULL-terminated C string.

REPY_FN_IF_CACHE

#define REPY_FN_IF_CACHE	(		helper_identifier,
			py_expression )

Value:

REPY_FN_IF_CACHE_INIT(helper_identifier) \
REPY_FN_IF_CACHE_STMT(helper_identifier, py_expression)

Initializes the helpers for a cached Pythonic if/else block, and constructs the first if statement, using a cached Python expression executed in the local scope.

This is the simplest way to handle Pythonic if/else blocks in C code, provided there are no additional C expressions that need to be evaluated as well.

See the REPY_IfStmtHelper section for more information.

Parameters

helper_identifier	The variable name of the REPY_IfStmtHelper object, as well as the prefix for the static REPY_IfStmtChain* object.
py_expression	The Python expression to evaluate within the scope. Should be a NULL-terminated C string.

REPY_FN_IF_CACHE_INIT

#define REPY_FN_IF_CACHE_INIT

(

helper_identifier

)

Value:

static REPY_IfStmtChain* helper_identifier ## _chain_root = NULL; \
REPY_IfStmtHelper* helper_identifier = REPY_DeferredCleanupHelper_AddIfStmtHelper(REPY_FN_AUTO_CLEANUP, REPY_IfStmtHelper_Create(&helper_identifier ## _chain_root)); \

Initializes the helpers for cached Pythonic if statements in the current scope.

This macro is used as part of REPY_FN_IF_CACHE, but you can invoke it manually if needed (for example, if you're mixing Python and C if statements in one if/else block).

See the REPY_IfStmtHelper section for more information.

Parameters

helper_identifier

The variable name of the REPY_IfStmtHelper object, as well as the prefix for the static REPY_IfStmtChain* object.

REPY_FN_IF_CACHE_STMT

#define REPY_FN_IF_CACHE_STMT	(		helper_identifier,
			py_expression )

Value:

if ( \
    REPY_IfStmtHelper_Step( \
        helper_identifier, \
        REPY_FN_GLOBAL_SCOPE, \
        REPY_FN_LOCAL_SCOPE, \
        py_expression, \
        __FILE_NAME__, \
        (char*) __func__, \
        __LINE__, \
        #helper_identifier \
    ) \
)

Constructs a if statement that uses a cached Python expression executed in the current scope.

This macro is used as part of REPY_FN_IF_CACHE and REPY_FN_ELIF_CACHE, but you can invoke it manually if needed (for example, if you're mixing Python and C if statements in one if/else block).

See the REPY_IfStmtHelper section for more information.

Parameters

helper_identifier	The variable name of the REPY_IfStmtHelper object. Needs to be the same as the value used when initializing this if/else block (using either REPY_FN_IF_CACHE_INIT or REPY_FN_IF_CACHE).
py_expression	The Python expression to evaluate within the scope. Should be a NULL-terminated C string.