Call and get both share a common syntax. As the names suggest, Call calls and Get gets. What does it call or get? It depends on PROC's value.
-PARAMS is a list of parameters and what do to with them. You can pass data in the parameters and you can also get data from them. The parameters list is separated by commas. Each parameter is combined of three values: type, source and destination. Type can be an integer, a string, etc. Source, which is the source of the parameter value, can be a NSIS register ($0, $1, $INSTDIR), the NSIS stack, a concrete value (5, "test", etc.) or nothing (null). Destination, which is the destination of the parameter value after the call returns, can can be a NSIS register, the NSIS stack or nothing which means no output is required. Either one of source or destination can also be a dot (`.') if it is not needed.
+PARAMS is a list of parameters and what do to with them. You can pass data in the parameters and you can also get data from them. The parameters list is separated by commas. Each parameter is combined of three values: type, source and destination. Type can be an integer, a string, etc. Source, which is the source of the parameter value, can be a NSIS register ($0, $1, $INSTDIR), the NSIS stack, a concrete value (5, "test", etc.) or nothing (null). Destination, which is the destination of the parameter value after the call returns, can be a NSIS register, the NSIS stack or nothing which means no output is required. Either one of source or destination can also be a dot (`.') if it is not needed.
RETURN is like a single parameter definition, but source is only used when creating callback functions. Normally source is a dot.