M core/interpreter.nim → core/interpreter.nim

@@ -14,7 +14,8 @@ "Symbol undefined",
   "Incorrect items on the stack",
   "Runtime error",
   "Two numbers are required on the stack",
-  "Division by zero"
+  "Division by zero",
+  "Two quotations are required on the stack"
 ]
 
 var ROOT*: ref MinScope = new MinScope
@@ -111,6 +112,14 @@ else:
     stderr.writeLine("$1 [$2,$3] `$4`: Error - $5" % [i.currSym.filename, $i.currSym.line, $i.currSym.column, i.currSym.symVal, msg])
     quit(int(status))
 
+template execute(i: In, body: stmt) {.immediate.}=
+  try:
+    body
+  except MinRuntimeError:
+    stderr.writeLine("$1 [$2,$3]: $4" % [i.currSym.filename, $i.currSym.line, $i.currSym.column, getCurrentExceptionMsg()])
+  except:
+    i.error(errSystem, getCurrentExceptionMsg())
+
 proc open*(i: In, stream:Stream, filename: string) =
   i.filename = filename
   i.parser.open(stream, filename)
@@ -130,12 +139,8 @@ if symbolProc.isNotNil:
       if i.unsafe:
         symbolProc(i) 
       else:
-        try:
-          symbolProc(i) 
-        except MinRuntimeError:
-          stderr.writeLine("$1 [$2,$3]: $4" % [i.currSym.filename, $i.currSym.line, $i.currSym.column, getCurrentExceptionMsg()])
-        except:
-          i.error(errSystem, getCurrentExceptionMsg())
+        i.execute:
+          i.symbolProc
     else:
       let sigilProc = i.scope.getSigil(sigil)
       if symbol.len > 1 and sigilProc.isNotNil:
@@ -144,12 +149,8 @@ i.stack.add(MinValue(kind: minString, strVal: sym))
         if i.unsafe:
           sigilProc(i) 
         else:
-          try:
-            sigilProc(i) 
-          except MinRuntimeError:
-            stderr.writeLine("$1 [$2,$3]: $4" % [i.currSym.filename, $i.currSym.line, $i.currSym.column, getCurrentExceptionMsg()])
-          except:
-            i.error(errSystem, getCurrentExceptionMsg())
+          i.execute:
+            i.sigilProc
       else:
         i.error(errUndefined, "Undefined symbol: '"&val.symVal&"'")
         return
@@ -175,10 +176,8 @@ 
 proc interpret*(i: In) = 
   var val: MinValue
   while i.parser.token != tkEof: 
-    try:
+    i.execute:
       val = i.parser.parseMinValue
-    except:
-      i.error errParser, getCurrentExceptionMsg()
     i.push val
 
 proc unquote*(i: In, name: string, q: var MinValue) =

M core/types.nim → core/types.nim

@@ -68,10 +68,6 @@ kind*: MinEventKind
     err*: MinParserError
     filename*: string
   MinStack* = seq[MinValue]
-  MinParsingError* = ref object of ValueError 
-  MinUndefinedError* = ref object of ValueError
-  MinRuntimeError* = ref object of SystemError
-    qVal*: seq[MinValue]
   MinInterpreter* = object
     stack*: MinStack
     pwd*: string
@@ -95,7 +91,13 @@ errUndefined,
     errIncorrect,
     errRuntime,
     errTwoNumbersRequired,
-    errDivisionByZero
+    errDivisionByZero,
+    errTwoQuotationsRequired
+  MinParsingError* = ref object of ValueError 
+  MinUndefinedError* = ref object of ValueError
+  MinInvalidError* = ref object of ValueError
+  MinRuntimeError* = ref object of SystemError
+    qVal*: seq[MinValue]
 
 proc isNotNil*[T](obj: T): bool =
   return not obj.isNil

M core/utils.nim → core/utils.nim

@@ -88,3 +88,14 @@ 
 template alias*[T](varname: untyped, value: var T) =
   var varname {.inject.}: type(value)
   shallowCopy varname, value
+
+proc reqTwoQuotations*(i: var MinInterpreter, a, b: var MinValue) =
+  a = i.pop
+  b = i.pop
+  if not a.isQuotation or not b.isQuotation:
+    raise MinInvalidError(msg: "Two quotations are required on the stack")
+
+proc reqQuotation*(i: var MinInterpreter, a: var MinValue) =
+  a = i.pop
+  if not a.isQuotation:
+    raise MinInvalidError(msg: "A quotation is required on the stack")

M lib/stack.nim → lib/stack.nim

@@ -19,9 +19,8 @@ .symbol("dup") do (i: In):
     i.push i.peek
   
   .symbol("dip") do (i: In):
-    var q = i.pop
-    if not q.isQuotation:
-      i.error errNoQuotation
+    var q: MinValue
+    i.reqQuotation q
     let v = i.pop
     i.unquote("<dip>", q)
     i.push v
@@ -33,14 +32,11 @@ i.push a
     i.push b
   
   .symbol("sip") do (i: In):
-    var a = i.pop
-    let b = i.pop
-    if a.isQuotation and b.isQuotation:
-      i.push b
-      i.unquote("<sip>", a)
-      i.push b
-    else:
-      i.error(errIncorrect, "Two quotations are required on the stack")
+    var a, b: MinValue 
+    i.reqTwoQuotations a, b
+    i.push b
+    i.unquote("<sip>", a)
+    i.push b
 
   .finalize()