Library Functions

 
Scheme_Env * scheme_new_frame(int n, int flags) 

Creates a new run-time environment frame with n slots. Currently, flags should always be 0. This frame can be used to extend the environment with (only one) scheme_extend_env.

 
Scheme_Env * scheme_new_compilation_frame(int n) 

Creates a new compile- or expand-time environment frame with n slots. This frame can be used to extend the environment with (only one) scheme_extend_env.

 
Scheme_Env * scheme_extend_env(Scheme_Env *frame, Scheme_Env *env) 

Creates a new (compile-time or run-time) environment by extending env with frame. WARNING: This is a macro -- frame is evaluated more than once!

 
void  scheme_add_binding(int index, Scheme_Object *val, Scheme_Env *frame) 

Sets the indexth value in frame to val.

 
void  scheme_add_compilation_binding(int index, Scheme_Object *sym, 
               Scheme_Env *frame) 

Sets the indexth variable name in frame to val.

 
void  scheme_get_binding(Scheme_Env *frame, Scheme_Object *val) 

Gets the indexth value/name from frame.

 
Scheme_Env * scheme_add_frame(Scheme_Object *vals, Scheme_Env *env, int flags) 

Extends the run-time environment env with a new frame; vals is a list of values to be put into the new frame. flags should be 0.

 
Scheme_Env * scheme_add_compilation_frame( Scheme_Object *names, 
                      Scheme_Env *env, int flags) 

Extends the compile- or expand-time environment env with a new frame; names is a list of values to be put into the new frame. Currently, flags should always be 0.

 
Scheme_Env * scheme_lengthen_compilation_frame( int count, Scheme_Env *frame) 

Creates a new compile-time frame to replace frame (making it larger). count new slots are added to frame. The new frame is added to the rest of the environment and returned.

 
void  scheme_frame_backinfo(Scheme_Env *orig, Scheme_Env *extended) 

When scheme_lengthen_compilation_frame is used to resize a compile-time frame, after compiling all exprssions that need the extended frame, apply this function to both the extended and original frames to propogate any information that sub-compilations (using the extended frame) may have added to the environment.

 
Scheme_Env * scheme_next_frame(Scheme_Env *env) 

Returns the frame for the static scope one level up.

 
int scheme_get_frame_settable(Scheme_Env *env) 

Returns the flag of the given compile-time environment which indicates whether values in the frame can be changed with set!.

 
int scheme_settable_frame(Scheme_Env *env, int settable) 

Set the flag of the given compile-time environment which indicates whether values in the frame can be changed with set!.

 
Scheme_Object * scheme_static_distance(Scheme_Object *sym, Scheme_Env *env,
                        int flags) 

Given a variable name (as a symbol) in sym, returns one of:

• static-distance coordinates for a variable in the compile-time environemnt env (type scheme_static_distance_type)
• static-distance coordinates for an indirect variable in the compile-time environemnt env (type scheme_static_distance_unbox_type)
• an unlinked global variable reference (with type scheme_variable_reference_type); if flags includes SCHEME_ELIM_CONST, an unlinked reference is never returned
• a global variable (with type scheme_variable_type); if flags includes SCHEME_ELIM_CONST and not SCHEME_GLOB_ALWAYS_REFERENCE and the variable is a contant, the variable's value is returned instead.
• a constant value; a value may be returned for a reference to a global variable or to a local constant installed with scheme_push_constant. Local constants are only returned when flags includes SCHEME_ENV_CONSTANTS_OK.

Use SCHEME_ENV_CONSTANTS_OK if a variable's value is needed, or SCHEME_GLOB_ALWAYS_REFERENCE if a variable is being mutated. Use SCHEME_ELIM_CONST when the compilation info record's can_optimize_constants value is TRUE and a variable's value is needed.

 
void  scheme_set_value(Scheme_Object *sd, Scheme_Object *val, Scheme_Env *env) 

Given a static-distance (or scheme_variable_type) value, sets the value in the run-time environment env to val.

 
void  scheme_check_identifier(char *form, Scheme_Object *id, char *where) 

Checks that id is a valid local variable identifier symbol. If an error is found, form is used as a syntax name to report the location of the error; if where is non-NULL, it should have the form ``in ...'' to further specify the location of the error.