M interpreter.nim → interpreter.nim

@@ -7,8 +7,10 @@ stack: TMinStack
     parser*: TMinParser
     currSym: TMinValue
     filename: string
+    debugging: bool
   TMinOperator* = proc (i: var TMinInterpreter)
   TMinError* = enum
+    errSystem,
     errParser,
     errGeneric,
     errEmptyStack,
@@ -20,6 +22,7 @@ errDivisionByZero
 
 
 const ERRORS: array [TMinError, string] = [
+  "A system error occurred",
   "A parsing error occurred",
   "A generic error occurred",
   "The stack is empty", 
@@ -32,10 +35,10 @@ ]
 
 var SYMBOLS* = initTable[string, TMinOperator]()
 
-proc newMinInterpreter*(): TMinInterpreter =
+proc newMinInterpreter*(debugging = false): TMinInterpreter =
   var s:TMinStack = newSeq[TMinValue](0)
   var p:TMinParser
-  var i:TMinInterpreter = TMinInterpreter(filename: "input", parser: p, stack: s, currSym: TMinValue(first: 0, last: 0, line: 0, kind: minSymbol, symVal: ""))
+  var i:TMinInterpreter = TMinInterpreter(filename: "input", parser: p, stack: s, debugging: debugging, currSym: TMinValue(first: 0, last: 0, line: 0, kind: minSymbol, symVal: ""))
   return i
 
 proc error*(i: TMinInterpreter, status: TMinError, message = "") =
@@ -50,11 +53,25 @@ 
 proc close*(i: var TMinInterpreter) = 
   i.parser.close();
 
+proc dump*(i: TMinInterpreter): string =
+  var s = ""
+  for item in i.stack:
+    s = s & $item & " "
+  return s.strip
+
+proc debug(i: var TMinInterpreter, value: string = "") =
+  if i.debugging: 
+    stderr.writeln("DEBUG: " &i.dump & value)
+
 proc push*(i: var TMinInterpreter, val: TMinValue) = 
   if val.kind == minSymbol:
     i.currSym = val
-    if SYMBOLS.hasKey val.symVal:
-      SYMBOLS[val.symVal](i) 
+    i.debug " "&val.symVal
+    if SYMBOLS.hasKey(val.symVal):
+      try:
+        SYMBOLS[val.symVal](i) 
+      except:
+        i.error(errSystem, getCurrentExceptionMsg())
     else:
       i.error(errUndefined, "Undefined symbol: '"&val.symVal&"'")
   else:
@@ -71,12 +88,6 @@ if i.stack.len > 0:
     return i.stack[i.stack.len-1]
   else:
     i.error(errEmptyStack)
-
-proc dump*(i: TMinInterpreter) =
-  for item in i.stack:
-    item.print
-    stdout.write " "
-  stdout.writeln ""
 
 proc interpret*(i: var TMinInterpreter) = 
   var val: TMinValue

M minim.nim → minim.nim

@@ -3,6 +3,8 @@ import parser, interpreter, primitives
 
 
 const version* = "0.1.0"
+var debugging = false
+var repl = false
 
 let usage* = "  MiNiM v" & version & " - a tiny concatenative programming language" & """
 
@@ -20,7 +22,7 @@ -v, --version     Print the program version
     -i, --interactive Starts MiNiM's Read Evel Print Loop"""
 
 proc minimStream(s: PStream, filename: string) =
-  var i = newMinInterpreter()
+  var i = newMinInterpreter(debugging)
   i.open(s, filename)
   discard i.parser.getToken() 
   i.interpret()
@@ -49,7 +51,7 @@ stderr.flushFile()
   minimStream(stream, filename)
 
 proc minimRepl*() = 
-  var i = newMinInterpreter()
+  var i = newMinInterpreter(debugging)
   var s = newStringStream("")
   i.open(s, "repl")
   setControlCHook(handleReplCtrlC)
@@ -66,7 +68,7 @@ i.parser.bufLen = i.parser.buf.len
     discard i.parser.getToken() 
     i.interpret()
     stdout.write "-> "
-    i.dump
+    echo i.dump
     
 ###
 
@@ -78,6 +80,8 @@ of cmdArgument:
       file = key
     of cmdLongOption, cmdShortOption:
       case key:
+        of "debug", "d":
+          debugging = true
         of "evaluate", "e":
           str = val
         of "help", "h":
@@ -85,8 +89,7 @@ echo usage
         of "version", "v":
           echo version
         of "interactive", "i":
-          minimRepl()
-          quit(0)
+          repl = true
     else:
       discard
 
@@ -94,5 +97,9 @@ if str != "":
   minimString(str)
 elif file != "":
   minimFile file
+elif repl:
+  minimRepl()
+  quit(0)
 else:
   minimFile stdin
+

M parser.nim → parser.nim

@@ -130,9 +130,9 @@ 
 proc raiseUndefinedError*(p:TMinParser, msg: string) {.noinline, noreturn.} =
   raise EMinUndefinedError(msg: errorMsg(p, msg))
 
-proc error(p: TMinParser, msg: string) = 
-  writeln(stderr, p.errorMsg(msg))
-  flushFile(stderr)
+#proc error(p: TMinParser, msg: string) = 
+#  writeln(stderr, p.errorMsg(msg))
+#  flushFile(stderr)
 
 proc parseNumber(my: var TMinParser) = 
   var pos = my.bufpos
@@ -411,20 +411,23 @@ discard getToken(p)
   else:
     raiseUndefinedError(p, "Undefined value: '"&p.a&"'")
 
-proc print*(a: TMinValue) =
+proc `$`*(a: TMinValue): string =
   case a.kind:
     of minSymbol:
-      stdout.write a.symVal
+      return a.symVal
     of minString:
-      stdout.write "\""&a.strVal&"\""
+      return "\""&a.strVal&"\""
     of minInt:
-      stdout.write a.intVal
+      return $a.intVal
     of minFloat:
-      stdout.write a.floatVal
+      return $a.floatVal
     of minQuotation:
-      stdout.write "[ "
+      var q = "[ "
       for i in a.qVal:
-        i.print
-        stdout.write " "
-      stdout.write "]"
+        q = q & $i & " "
+      q = q & "]"
+      return q
+
+proc print*(a: TMinValue) =
+  stdout.write($a)
 

M primitives.nim → primitives.nim

@@ -56,7 +56,7 @@ 
 # Operations on the whole stack
 
 minsym "dump":
-  i.dump
+  echo i.dump
 
 # Operations on quotations or strings
 
@@ -166,7 +166,21 @@ i.push newFloat(b.intVal.float / a.floatVal)
     else:
       i.error(errTwoNumbersRequired)
 
+# Language constructs
 
+minsym "def":
+  let q1 = i.pop
+  let q2 = i.pop
+  if q1.isQuotation and q2.isQuotation:
+    if q1.qVal.len == 1 and q1.qVal[0].kind == minSymbol:
+      minsym q1.qVal[0].symVal:
+        for item in q2.qVal:
+          i.push item
+    else:
+      i.error(errIncorrect, "The top quotation must contain only one symbol value")
+  else:
+    i.error(errIncorrect, "Two quotations or two strings is required on the stack")
 
 minalias "&", "concat"
 minalias "%", "print"
+minalias ":", "def"