🐐 Compound assignment

README.md

@@ -22,6 +22,18 @@ Variables are set with the `DESIGNA` and `VT` keywords. Type is inferred.
 
 Variable can consist of lower-case letters, numbers, as well as `_`.
 
+### Compound assignment
+
+`AVGE` (+=) and `MINVE` (-=) are shorthand for incrementing or decrementing a variable:
+
+![Compound assignment](snippets/compound.png)
+
+```
+> VIII
+```
+
+`x AVGE III` is equivalent to `DESIGNA x VT x + III`.
+
 ## Data types
 ### NVLLVS
 `NVLLVS` is a special kind of data type in `CENTVRION`, similar to the `null` value in many other languages. `NVLLVS` can be 0 if evaluated as an int or float, or an empty string if evaluated as a string. `NVLLVS` cannot be evaluated as a boolean.

centvrion/lexer.py

@@ -5,6 +5,7 @@ valid_characters = '|'.join(list("abcdefghiklmnopqrstvxyz_"))
 keyword_tokens = [("KEYWORD_"+i, i) for i in [
   "AETERNVM",
   "ALVID",
+  "AVGE",
   "AVT",
   "DEFINI",
   "DESIGNA",
@@ -19,6 +20,7 @@ keyword_tokens = [("KEYWORD_"+i, i) for i in [
   "FALSITAS",
   "INVOCA",
   "IN",
+  "MINVE",
   "MINVS",
   "NON",
   "NVLLVS",

centvrion/parser.py

@@ -74,6 +74,14 @@ class Parser():
     def statement_designa_index(tokens):
       return ast_nodes.DesignaIndex(tokens[1], tokens[3], tokens[6])
 
+    @self.pg.production('statement : id KEYWORD_AVGE expression')
+    def statement_avge(tokens):
+      return ast_nodes.Designa(tokens[0], ast_nodes.BinOp(tokens[0], tokens[2], "SYMBOL_PLUS"))
+
+    @self.pg.production('statement : id KEYWORD_MINVE expression')
+    def statement_minve(tokens):
+      return ast_nodes.Designa(tokens[0], ast_nodes.BinOp(tokens[0], tokens[2], "SYMBOL_MINUS"))
+
     @self.pg.production('statement : expression')
     def statement_expression(tokens):
       return ast_nodes.ExpressionStatement(tokens[0])

language/main.tex

@@ -30,6 +30,8 @@
       \multicolumn{3}{|c|}{\textbf{Statements}} \\ \hline
         \languageline{statement}{\textit{expression}} \\
         \languageline{statement}{\texttt{DESIGNA} \textbf{id} \texttt{VT} \textit{expression}} \\
+        \languageline{statement}{\textbf{id} \texttt{AVGE} \textit{expression}} \\
+        \languageline{statement}{\textbf{id} \texttt{MINVE} \textit{expression}} \\
         \languageline{statement}{\texttt{DEFINI} \textbf{id} \texttt{(} \textit{optional-ids} \texttt{)} \texttt{VT} \textit{scope}} \\
         \languageline{statement}{\textit{if-statement}} \\
         \languageline{statement}{\texttt{DVM} \textit{expression} \texttt{FACE} \textit{scope}} \\

snippets/compound.cent

@@ -0,0 +1,3 @@
+DESIGNA x VT V
+x AVGE III
+DICE(x)

snippets/syntaxes/centvrion.sublime-syntax

@@ -65,7 +65,7 @@ contexts:
       scope: support.class.module.centvrion
 
   keywords:
-    - match: '\b(AETERNVM|ALVID|AVT|DEFINI|DESIGNA|DONICVM|DVM|ERVMPE|EST|ET|FACE|INVOCA|IN|MINVS|NON|PER|PLVS|REDI|RELIQVVM|SI|TVNC|VSQVE|VT|CVM)\b'
+    - match: '\b(AETERNVM|ALVID|AVGE|AVT|CONTINVA|DEFINI|DESIGNA|DONICVM|DVM|ERVMPE|EST|ET|FACE|INVOCA|IN|MINVE|MINVS|NON|PER|PLVS|REDI|RELIQVVM|SI|TVNC|VSQVE|VT|CVM)\b'
       scope: keyword.control.centvrion
 
   operators:

tests.py

@@ -265,6 +265,31 @@ assignment_tests = [
                  Designa(ID("x"), BinOp(ID("x"), Numeral("I"), "SYMBOL_PLUS")),
                  ExpressionStatement(ID("x"))]),
     ValInt(3)),
+  # Compound assignment — AVGE (+=)
+  ("DESIGNA x VT V\nx AVGE III\nx",
+    Program([], [Designa(ID("x"), Numeral("V")),
+                 Designa(ID("x"), BinOp(ID("x"), Numeral("III"), "SYMBOL_PLUS")),
+                 ExpressionStatement(ID("x"))]),
+    ValInt(8)),
+  # Compound assignment — MINVE (-=)
+  ("DESIGNA x VT X\nx MINVE III\nx",
+    Program([], [Designa(ID("x"), Numeral("X")),
+                 Designa(ID("x"), BinOp(ID("x"), Numeral("III"), "SYMBOL_MINUS")),
+                 ExpressionStatement(ID("x"))]),
+    ValInt(7)),
+  # AVGE with complex expression
+  ("DESIGNA x VT I\nx AVGE II + III\nx",
+    Program([], [Designa(ID("x"), Numeral("I")),
+                 Designa(ID("x"), BinOp(ID("x"), BinOp(Numeral("II"), Numeral("III"), "SYMBOL_PLUS"), "SYMBOL_PLUS")),
+                 ExpressionStatement(ID("x"))]),
+    ValInt(6)),
+  # AVGE inside a loop (DONICVM range is exclusive of upper bound: I VSQVE III = [1, 2])
+  ("DESIGNA s VT NVLLVS\nDONICVM i VT I VSQVE III FACE {\ns AVGE i\n}\ns",
+    Program([], [Designa(ID("s"), Nullus()),
+                 PerStatement(DataRangeArray(Numeral("I"), Numeral("III")), ID("i"),
+                   [Designa(ID("s"), BinOp(ID("s"), ID("i"), "SYMBOL_PLUS"))]),
+                 ExpressionStatement(ID("s"))]),
+    ValInt(3)),
 ]
 
 class TestAssignment(unittest.TestCase):