Fixed precedence of is added beta support for the as operator for casting

src/compiler.nim

@@ -66,9 +66,10 @@ type
         Assign,
         Or,
         And,
-        Is,
         Eq,
         Comp,
+        As,
+        Is,
         Term,
         Factor,
         Unary,
@@ -319,6 +320,8 @@ proc binary(self: Compiler, canAssign: bool) =
             self.emitByte(OpCode.Band)
         of TokenType.IS:
             self.emitByte(OpCode.Is)
+        of TokenType.AS:
+            self.emitByte(OpCode.As)
         else:
             discard # Unreachable
 
@@ -1149,7 +1152,9 @@ var rules: array[TokenType, ParseRule] = [
     makeRule(nil, binary, Precedence.Term), # BAND
     makeRule(nil, binary, Precedence.Term), # BOR
     makeRule(unary, nil, Precedence.None), # TILDE
-    makeRule(nil, binary, Precedence.Is)   # IS
+    makeRule(nil, binary, Precedence.Is),   # IS
+    makeRule(nil, binary, Precedence.As)   # AS
+
 ]
 
 

src/lexer.nim

@@ -56,9 +56,8 @@ const RESERVED = to_table({
                 "this": TokenType.THIS, "super": TokenType.SUPER,
                 "del": TokenType.DEL, "break": TokenType.BREAK,
                 "continue": TokenType.CONTINUE, "inf": TokenType.INF,
-                "nan": TokenType.NAN,
-                "is": TokenType.IS,
-                "not": TokenType.NEG})
+                "nan": TokenType.NAN, "is": TokenType.IS,
+                "not": TokenType.NEG, "as": TokenType.AS})
 type
     Lexer* = ref object
         source*: string

src/meta/opcode.nim

@@ -69,7 +69,8 @@ type
         Bor,
         Band,
         Bnot,
-        Is
+        Is,
+        As
 
 
     
@@ -81,7 +82,7 @@ const simpleInstructions* = {OpCode.Return, OpCode.Add, OpCode.Multiply,
                              OpCode.Xor, OpCode.Not, OpCode.Equal,
                              OpCode.Greater, OpCode.Less, OpCode.GetItem,
                              OpCode.Slice, OpCode.Pop, OpCode.Negate,
-                             OpCode.Is}
+                             OpCode.Is, OpCode.As}
 const constantInstructions* = {OpCode.Constant, OpCode.DefineGlobal,
                          OpCode.GetGlobal, OpCode.SetGlobal,
                          OpCode.DeleteGlobal}

src/meta/token.nim

@@ -29,7 +29,7 @@ type
     WHILE, DEL, BREAK, EOF,
     COLON, CONTINUE, CARET,
     SHL, SHR, NAN, INF, BAND,
-    BOR, TILDE, IS
+    BOR, TILDE, IS, AS
   Token* = ref object
     kind*: TokenType
     lexeme*: string

src/types/japlString.nim

@@ -19,6 +19,7 @@ import baseObject
 import numbers
 import ../memory
 import strutils
+import strformat
 
 
 type
@@ -62,8 +63,10 @@ proc isFalsey*(self: ptr String): bool =
 
 
 proc stringify*(self: ptr String): string =
-    result = self.toStr()
-
+    if self.len == 0:
+        result = "''"
+    else:
+        result = self.toStr()
 
 proc typeName*(self: ptr String): string =
     return "string"

src/types/methods.nim

@@ -24,6 +24,8 @@ import japlNil
 import numbers
 import native
 
+import parseutils
+
 
 proc typeName*(self: ptr Obj): string =
     ## Returns the name of the object's type
@@ -403,6 +405,46 @@ proc gt*(self: ptr Obj, other: ptr Obj): bool =
             raise newException(NotImplementedError, "")
 
 
+proc objAs*(self: ptr Obj, other: ObjectType): ptr Obj = 
+    ## Returns the result of self as other
+    ## (casts self to other's type)
+    
+    # TODO -> This is in beta!
+    case other:
+        of ObjectType.String:
+            result = stringify(self).asStr()
+        of ObjectType.Integer:
+            case self.kind:
+                of ObjectType.String:
+                    var intVal: int
+                    discard parseInt(cast[ptr String](self).toStr(), intVal)
+                    result = intVal.asInt()
+                of ObjectType.Float:
+                    var floatVal: float64
+                    discard (parseFloat(cast[ptr Float](self).stringify(), floatVal))
+                    result = int(floatVal).asInt()
+                of ObjectType.Integer:
+                    result = self
+                else:
+                    raise newException(NotImplementedError, "")
+        of ObjectType.Float:
+            case self.kind:
+                of ObjectType.String:
+                    var floatVal: float64
+                    discard parseFloat(cast[ptr String](self).toStr(), floatVal)
+                    result = floatVal.asFloat()
+                of ObjectType.Integer:
+                    var intVal: int
+                    discard parseInt(cast[ptr Integer](self).stringify(), intVal)
+                    result = float(intVal).asFloat()
+                of ObjectType.Float:
+                    result = self
+                else:
+                    raise newException(NotImplementedError, "")
+                    
+        else:
+            raise newException(NotImplementedError, "")
+
 
 ## Utilities to inspect JAPL objects
 

src/vm.nim

@@ -326,6 +326,7 @@ proc readLongConstant(self: CallFrame): ptr Obj =
     copyMem(idx.addr, unsafeAddr(arr), sizeof(arr))
     result = self.function.chunk.consts[idx]
 
+
 proc showRuntime*(self: VM, frame: CallFrame, iteration: uint64) = 
     ## Shows debug information about the current
     ## state of the virtual machine
@@ -526,6 +527,14 @@ proc run(self: VM, repl: bool): InterpretResult =
                 var right = self.pop()
                 var left = self.pop()
                 self.push(self.getBoolean(left == right))
+            of OpCode.As:
+                var right = self.pop()
+                var left = self.pop()
+                try:
+                    self.push(objAs(left, right.kind))
+                except NotImplementedError:
+                    self.error(newTypeError(&"unsupported binary operator 'as' for objects of type '{left.typeName()}' and '{right.typeName()}'"))
+                    return RuntimeError
             of OpCode.GetItem:
                 # TODO: More generic method
                 if not self.slice():
@@ -617,6 +626,7 @@ proc run(self: VM, repl: bool): InterpretResult =
             of OpCode.Return:
                 var retResult = self.pop()
                 if repl and not self.lastPop.isNil() and self.frameCount == 1:
+                    # TODO -> Make this more efficient (move into japl.nim?)
                     # Prints the last expression to stdout as long as we're
                     # in REPL mode, the expression isn't nil and we're at the
                     # top-level code

tests/japl/booleans.jpl

@@ -9,7 +9,7 @@ print(true and 2);//output:2
 print(false or 5);//output:5
 print(0 or 4);//output:4
 print(0 and true);//output:0
-print("" and true);//output:
+print("" and true);//output:''
 print("" or true);//output:true
 print(1 or 2 or 3 or 4);//output:1
 print(1 and 2 and 3 and 4);//output:4