Language extension

Language extension mk Tue, 03/30/2010 - 16:27

8.12 Language Extensions

Iterators over scalar ranges are often needed, also at the MAL level. The barrier and control primitives are sufficient to mimic them directly.

The modules located in the kernel directory should not rely on the MAL datastructures. That's why we have to deal with some bat operations here and delegate the signature to the proper module upon loading.

Running a script is typically used to initialize a context. Therefore we need access to the runtime context. For the call variants we have to determine an easy way to exchange the parameter/return values.

module language;
pattern call(s:str):void
address CMDcallString comment "Evaluate a MAL string program.";
pattern call(s:bat[:oid,:str]):void
address CMDcallBAT comment "Evaluate a program stored in a BAT.";
pattern source(f:str):void
address CMDevalFile comment "Merge the instructions stored in the file with the current program.";

command raise(msg:str) :str
address CMDraise
comment "Raise an exception labeled
    with a specific message.";
command assert(v:bit,term:str):void
address MALassertBit;
command assert(v:sht,term:str):void
address MALassertSht;
command assert(v:int,term:str):void
address MALassertInt;
command assert(v:lng,term:str):void
address MALassertLng;
command assert(v:str,term:str):void
address MALassertStr;
command assert(v:oid,term:str):void
address MALassertOid;
pattern assert(v:any_1,pname:str,oper:str,val:any_2):void
address MALassertTriple
comment "Assertion test.";

pattern dataflow():bit
address MALstartDataflow
comment "The current guarded block is executed using dataflow control. ";

pattern sink(v:any...):void
address MALgarbagesink
comment "Variables to be considered together when triggering garbage collection.
Used in the dataflow blocks to avoid early release of values.";

pattern pass(v:any_1):any_1
address MALpass
comment "Cheap instruction to disgard storage while retaining the dataflow dependency";

pattern register(m:str,f:str,code:str,help:str):void
address CMDregisterFunction
comment"Compile the code string to MAL and register it as a function.";