Parser bugfixes + small changes in initializer methods for parser and compiler. Added generic error type for NimVM parsing exceptions

src/backend/compiler.nim

@@ -30,20 +30,19 @@ type
         ast: seq[ASTNode]
         current: int
         file: string
+        # Keeps track of all identifiers
+        # in the code
         names: seq[IdentifierWrapper]
     
     CompileError* = object of NimVMException
 
 
-proc initCompiler*(self: Compiler = nil, ast: seq[ASTNode], file: string): Compiler =
-    ## Initializes a new Compiler object or
-    ## resets the state of an existing one
-    if self != nil:
-        result = self
-    self.ast = ast
-    self.current = 0
-    self.file = file
-    self.names = @[]
+proc initCompiler*(): Compiler =
+    ## Initializes a new Compiler object
+    result.ast = @[]
+    result.current = 0
+    result.file = ""
+    result.names = @[]
 
 
 proc peek(self: Compiler, distance: int = 0): ASTNode =

src/backend/meta/errors.nim

@@ -0,0 +1,15 @@
+# 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.
+
+type NimVMException* = ref object of CatchableError

src/backend/parser.nim

@@ -37,11 +37,8 @@ type
         ## A parse error
 
 
-proc initParser*(self: Parser = nil): Parser = 
+proc initParser*(): Parser = 
     ## Initializes a new Parser object
-    ## or resets an already existing one
-    if self != nil:
-        result = self
     new(result)
     result.current = 0
     result.file = ""
@@ -796,8 +793,9 @@ proc declaration(self: Parser): ASTNode =
 
 proc parse*(self: Parser, tokens: seq[Token], file: string): seq[ASTNode] =
     ## Parses a series of tokens into an AST node
-    discard self.initParser()
     self.tokens = tokens
     self.file = file
+    self.current = 0
+    self.context = Script
     while not self.done():
         result.add(self.declaration())