🐐 Step in for loop

centvrion/ast_nodes.py

@@ -369,19 +369,28 @@ class DataArray(Node):
 
 
 class DataRangeArray(Node):
-  def __init__(self, from_value, to_value) -> None:
+  def __init__(self, from_value, to_value, step=None) -> None:
     self.from_value = from_value
     self.to_value = to_value
+    self.step = step
 
   def __eq__(self, other):
-    return type(self) == type(other) and self.from_value == other.from_value and self.to_value == other.to_value
+    return (type(self) == type(other)
+            and self.from_value == other.from_value
+            and self.to_value == other.to_value
+            and self.step == other.step)
 
   def __repr__(self) -> str:
-    content_string = rep_join([self.from_value, self.to_value])
-    return f"RangeArray([{content_string}])"
+    parts = [self.from_value, self.to_value]
+    if self.step is not None:
+      parts.append(self.step)
+    return f"RangeArray([{rep_join(parts)}])"
 
   def print(self):
-    return f"[{self.from_value.print()} VSQVE {self.to_value.print()}]"
+    base = f"[{self.from_value.print()} VSQVE {self.to_value.print()}"
+    if self.step is not None:
+      base += f" GRADV {self.step.print()}"
+    return base + "]"
 
   def _eval(self, vtable):
     vtable, from_val = self.from_value.eval(vtable)
@@ -390,7 +399,25 @@ class DataRangeArray(Node):
       raise CentvrionError("Range bounds must be numbers")
     from_int = from_val.value() or 0
     to_int = to_val.value() or 0
-    return vtable, ValList([ValInt(i) for i in range(from_int, to_int + 1)])
+    if self.step is None:
+      return vtable, ValList([ValInt(i) for i in range(from_int, to_int + 1)])
+    vtable, step_val = self.step.eval(vtable)
+    if not isinstance(step_val, ValInt):
+      raise CentvrionError("Range step must be a number")
+    step_int = step_val.value()
+    if step_int == 0:
+      raise CentvrionError("Range step cannot be zero")
+    items = []
+    i = from_int
+    if step_int > 0:
+      while i <= to_int:
+        items.append(ValInt(i))
+        i += step_int
+    else:
+      while i >= to_int:
+        items.append(ValInt(i))
+        i += step_int
+    return vtable, ValList(items)
 
 
 class DataDict(Node):

centvrion/compiler/emit_expr.py

@@ -166,10 +166,21 @@ def emit_expr(node, ctx):
     hi_lines, hi_var = emit_expr(node.to_value, ctx)
     tmp = ctx.fresh_tmp()
     i_var = ctx.fresh_tmp()
-    cap = f"({hi_var}.ival >= {lo_var}.ival ? (int)({hi_var}.ival - {lo_var}.ival + 1) : 0)"
-    lines = lo_lines + hi_lines + [
-      f"CentValue {tmp} = cent_list_new({cap});",
-      f"for (long {i_var} = {lo_var}.ival; {i_var} <= {hi_var}.ival; {i_var}++) {{",
+    if node.step is None:
+      cap = f"({hi_var}.ival >= {lo_var}.ival ? (int)({hi_var}.ival - {lo_var}.ival + 1) : 0)"
+      lines = lo_lines + hi_lines + [
+        f"CentValue {tmp} = cent_list_new({cap});",
+        f"for (long {i_var} = {lo_var}.ival; {i_var} <= {hi_var}.ival; {i_var}++) {{",
+        f"  cent_list_push(&{tmp}, cent_int({i_var}));",
+        "}",
+      ]
+      return lines, tmp
+    step_lines, step_var = emit_expr(node.step, ctx)
+    lines = lo_lines + hi_lines + step_lines + [
+      f'if ({step_var}.type != CENT_INT) cent_type_error("Range step must be a number");',
+      f'if ({step_var}.ival == 0) cent_runtime_error("Range step cannot be zero");',
+      f"CentValue {tmp} = cent_list_new(0);",
+      f"for (long {i_var} = {lo_var}.ival; ({step_var}.ival > 0 ? {i_var} <= {hi_var}.ival : {i_var} >= {hi_var}.ival); {i_var} += {step_var}.ival) {{",
       f"  cent_list_push(&{tmp}, cent_int({i_var}));",
       "}",
     ]

centvrion/lexer.py

@@ -21,6 +21,7 @@ keyword_tokens = [("KEYWORD_"+i, i) for i in [
   "FAC",
   "FALSITAS",
   "FVNCTIO",
+  "GRADV",
   "HAVD_MINVS",
   "HAVD_PLVS",
   "INVOCA",

centvrion/parser.py

@@ -276,6 +276,11 @@ class Parser():
       range_array = ast_nodes.DataRangeArray(tokens[3], tokens[5])
       return ast_nodes.PerStatement(range_array, tokens[1], tokens[8])
 
+    @self.pg.production('donicum_statement : KEYWORD_DONICVM id KEYWORD_VT expression KEYWORD_VSQVE expression KEYWORD_GRADV expression KEYWORD_FAC SYMBOL_LCURL statements SYMBOL_RCURL')
+    def donicum_step(tokens):
+      range_array = ast_nodes.DataRangeArray(tokens[3], tokens[5], tokens[7])
+      return ast_nodes.PerStatement(range_array, tokens[1], tokens[10])
+
     # expressions
     @self.pg.production('expressions : SYMBOL_LPARENS expression_list')
     def expressions(tokens):
@@ -394,6 +399,10 @@ class Parser():
     def range_array(tokens):
       return ast_nodes.DataRangeArray(tokens[1], tokens[3])
 
+    @self.pg.production('expression : SYMBOL_LBRACKET expression KEYWORD_VSQVE expression KEYWORD_GRADV expression SYMBOL_RBRACKET')
+    def range_array_step(tokens):
+      return ast_nodes.DataRangeArray(tokens[1], tokens[3], tokens[5])
+
     @self.pg.production('expression : expression SYMBOL_LBRACKET expression SYMBOL_RBRACKET', precedence='INDEX')
     def array_index(tokens):
       return ast_nodes.ArrayIndex(tokens[0], tokens[2])