Made print a variadic function and added clock() for benchmarking

examples/fib.jpl

@@ -6,4 +6,4 @@ fun fib(n) {
 }
 
 
-fib(20);  //TODO: Benchmark this
+print(fib(15));  //TODO: Benchmark this

src/japl.nim

@@ -25,7 +25,7 @@ import stdlib
 
 proc repl() =
     var bytecodeVM = initVM()
-    stdlibInit(bytecodeVM)
+    bytecodeVM.stdlibInit()
     echo JAPL_VERSION_STRING
     echo &"[Nim {NimVersion} on {hostOs} ({hostCPU})]"
     when DEBUG_TRACE_VM:
@@ -75,6 +75,7 @@ proc main(file: string = "") =
         except IOError:
             echo &"Error: '{file}' could not be read, probably you don't have the permission to read it"
         var bytecodeVM = initVM()
+        bytecodeVM.stdlibInit()
         when DEBUG_TRACE_VM:
             echo "Debugger enabled, expect verbose output\n"
             echo "==== VM Constants ====\n"

src/stdlib.nim

@@ -1,15 +1,53 @@
+# Copyright 2020 Mattia Giambirtone
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
-# this implements stdlib functions for JAPL
+# Implementations of builtin functions and modules
 
 import vm
 import types/native
 import types/baseObject
 import types/japlNil
+import types/numbers
 import types/methods
+import times
+
+
 
 proc natPrint(args: seq[ptr Obj]): tuple[ok: bool, result: ptr Obj] =
-    echo args[0].stringify()
+    ## Native function print
+    ## Prints an object representation
+    ## to stdout. If more than one argument
+    ## is passed, they will be printed separated
+    ## by a space
+    var res = ""
+    for arg in args:
+        res = res & arg.stringify() & " "
+    echo res
     return (ok: true, result: asNil())
 
+
+proc natClock(args: seq[ptr Obj]): tuple[ok: bool, result: ptr Obj] =
+    ## Native function clock
+    ## Returns the current unix
+    ## time (also known as epoch)
+    ## with subsecond precision
+
+    # TODO: Move this to a separate module once we have imports
+
+    result = (ok: true, result: getTime().toUnixFloat().asFloat())
+
+
 template stdlibInit*(vm: VM) =
-    vm.defineGlobal("print", newNative("print", natPrint, 1))
+    vm.defineGlobal("print", newNative("print", natPrint, -1))
+    vm.defineGlobal("clock", newNative("clock", natClock, 0))

src/vm.nim

@@ -231,8 +231,9 @@ proc call(self: var VM, function: ptr Function, argCount: int): bool =
     self.frameCount += 1
     return true
 
+
 proc call(self: var VM, native: ptr Native, argCount: int): bool =
-    if argCount != native.arity:
+    if argCount != native.arity and native.arity != -1:
         self.error(newTypeError(&"function '{stringify(native.name)}' takes {native.arity} argument(s), got {argCount}"))
         return false
     let slot = self.stack.high() - argCount + 1
@@ -242,14 +243,15 @@ proc call(self: var VM, native: ptr Native, argCount: int): bool =
     let nativeResult = native.nimproc(args)
     if not nativeResult.ok:
         self.error(cast[ptr JaplException](nativeResult.result))
-        # assumes that all native procs behave well, and if not ok, they 
+        # assumes that all native procs behave well, and if not ok, they
         # only return japl exceptions
     for i in countup(slot - 1, self.stack.high()):
         discard self.pop() # TODO once stack is a custom datatype,
         # just reduce its length
-    self.push(nativeResult.result) 
+    self.push(nativeResult.result)
     return true
 
+
 proc callObject(self: var VM, callee: ptr Obj, argCount: uint8): bool =
     ## Wrapper around call() to do type checking
     if callee.isCallable():