x65/docs/eval_functions.md

Eval Functions

Eval Functions are used like symbols in expressions but are always followed by parenthesis with optional arguments.

DEFINED, DEF

.if .def(symbol)
.endif

Evaluates to 1 if the symbol has been defined or 0 if it has not been encountered to this point in the current assembly.

REFERENCED

.if .referenced(symbol)
.endif

Evaluates to 1 if the symbol has been referenced in the current assembly, the symbol should be defined at this point.

BLANK

.if .blank()
.endif

Evaluates to 1 if the contents within the parenthesis is empty, primarily for use within macros.

CONST

if .const(symbol)
.endif

Evaluates to 1 if the symbol has been declared CONST, the symbol should be defined at this point.

SIZEOF

STRUCT Module {
	word Init
	word Update
	word Shutdown
}

ds SIZEOF( Module )

Returns the byte size of a given struct.

TRIGSIN

Not implemented, experimental math feature, currently returns 0.