move arity checking to its own op

chunk.nim

@@ -5,7 +5,7 @@ import value
 
 type
   OpCode* = enum
-    opReturn, opCall, # functions
+    opReturn, opCall, opCheckArity # functions
     opPop, opPopSA, opPopA # pop
     opPrint, # print
     opNegate, opNot # unary
@@ -87,6 +87,7 @@ const constantInstructions = {
 const shortArgInstructions = {
   opPopSA,
   opCall,
+  opCheckArity,
 }
 const argInstructions = {
   opPopA,

compiler.nim

@@ -633,6 +633,9 @@ proc parseFunct(comp: Compiler) =
   if params.len > shortArgMax:
     comp.error("Too many parameters.")
 
+  comp.writeChunk(0, opCheckArity) # runtime arity check
+  comp.writeChunk(0, params.len.uint8)
+
   for i in countup(1, params.len):
     comp.stackIndex = i
     comp.addLocal(params[i-1], 0)
@@ -645,7 +648,7 @@ proc parseFunct(comp: Compiler) =
   dec comp.stackIndex # the previous end scope did not put anything on the stack, it is jumped over
 
   # get konvalue functions:
-  let konFunct = newKonFunction(functII, params.len.uint8)
+  let konFunct = newNdFunction(functII)
 
   # end of function declaration:
   comp.patchJump(jumpOverBody)

config.nim

@@ -19,7 +19,7 @@ const lineEditor = leRdstdin
 when lineEditor == leRdstdin:
   import rdstdin
 
-proc konLineEditor*: string =
+proc ndLineEditor*: string =
   proc ctrlc = 
     raise newException(ReadlineInterruptedException, "Ctrl+C/D pressed.")
   when lineEditor == leBasic:

main.nim

@@ -21,7 +21,7 @@ proc interpret(name: string, source: string): Result =
 proc repl =
   while true:
     try:
-      let line = konLineEditor()
+      let line = ndLineEditor()
       if line.len > 0:
         discard interpret("repl", line)
     except ReadlineInterruptedException:

value.nim

@@ -20,8 +20,7 @@ type
       of ndString:
         stringValue*: string
       of ndFunct:
-        sdfga*: string # WHY IS THIS STRING WHEN HERE EVEN THO USELESS SPEEDING THE BENCHMARK UP
-        arity*: uint8 # number of arguments
+        placeholder*: string
         entryII*: int # entry instruction index
       of errorTypes:
         message*: string
@@ -72,7 +71,6 @@ proc equal*(val, right: NdValue): bool =
         val.stringValue == right.stringValue
       of ndFunct:
         val.entryII == right.entryII
-        # same entry II/module but diff arity is a bug
       of errorTypes:
         false # error comparison is undefined
 
@@ -87,13 +85,13 @@ proc toNdValue*(val: bool): NdValue =
 proc toNdValue*(val: string): NdValue =
   NdValue(ndType: ndString, stringValue: val)
 
-proc newKonFunction*(ii: int, arity: uint8): NdValue =
-  NdValue(ndType: ndFunct, entryII: ii, arity: arity)
+proc newNdFunction*(ii: int): NdValue =
+  NdValue(ndType: ndFunct, entryII: ii)
 
 proc toNdValue*: NdValue =
   NdValue(ndType: ndNil)
 
-proc konError*(msg: string): NdValue =
+proc ndError*(msg: string): NdValue =
   NdValue(ndType: ndError, message: msg)
 
 # NatReturn misc
@@ -147,10 +145,10 @@ proc `<`*(val: NdValue, right: NdValue): NdValue =
   if val.ndType == ndFloat and right.ndType == ndFloat:
     return toNdValue(val.floatValue < right.floatValue)
   else:
-    return konError(&"Attempt to compare types {val.ndType} and {right.ndType}.")
+    return ndError(&"Attempt to compare types {val.ndType} and {right.ndType}.")
 
 proc `>`*(val: NdValue, right: NdValue): NdValue =
   if val.ndType == ndFloat and right.ndType == ndFloat:
     return toNdValue(val.floatValue > right.floatValue)
   else:
-    return konError(&"Attempt to compare types {val.ndType} and {right.ndType}.")
+    return ndError(&"Attempt to compare types {val.ndType} and {right.ndType}.")

vm.nim

@@ -62,10 +62,6 @@ proc run*(chunk: Chunk): InterpretResult =
     result = ip[].int
     ip = ip.padd(1)
   
-  proc readUI8Noconv(): uint8 =
-    result = ip[]
-    ip = ip.padd(1)
-
   proc readDU8(): int =
     result = ip.DU8ptrToInt
     ip = ip.padd(argSize)
@@ -204,21 +200,23 @@ proc run*(chunk: Chunk): InterpretResult =
       of opLoop:
         let offset = readDU8()
         ip = ip.psub(offset)
+      of opCheckArity:
+        let arity = readUI8()
+        let argcount = stack.high() - frameBottom
+        if arity != argcount:
+          runtimeError(&"Wrong number of arguments, expected {arity}, got {argcount}.")
+          break
       of opCall:
         # create the call env
         # current stack before opCall:
         # ... <funct obj> <arg1> <arg2> <arg3>
         # opCall converts it to this
         # ... <ret val> <arg1> <arg2> <arg3>
-        let argcountUint8 = readUI8Noconv()
-        let argcount = argcountUint8.int
+        let argcount = readUI8()
         let funct = stack[stack.high - argcount]
         if funct.ndType != ndFunct:
           runtimeError("Attempt to call a non-funct (a defunct?).") # here is a bad defunct joke
           break
-        if funct.arity != argcountUint8:
-          runtimeError(&"Wrong number of arguments, expected {funct.arity}, got {argcount}.")
-          break
 
         stack[stack.high - argcount] = toNdValue() # replace the function with nil: this is the return value slot