Trial improved expression parsing.

finesse/script/parser.py

@@ -407,8 +407,6 @@ class _KatInstructionLEX(Lexer):
 
     FUNCTION_NAME = "cos|sin"
     PARAMETER = "&[a-zA-Z_][a-zA-Z0-9_.]*"
-    PLUS = TOKEN_MAP["PLUS"]
-    MINUS = TOKEN_MAP["MINUS"]
     TIMES = TOKEN_MAP["TIMES"]
     DIVIDE = TOKEN_MAP["DIVIDE"]
     COMMA = TOKEN_MAP["COMMA"]
@@ -426,7 +424,10 @@ class _KatInstructionLEX(Lexer):
         return t
 
     # Number token including scientific notation, float, or +/- inf.
-    @_(r"[+-]?inf", r"[+-]?(\d+\.\d*|\d*\.\d+|\d+)([eE]-?\d*\.?\d*)?j?([pnumkMGT])?")
+    @_(
+        r"(\B[+-])?inf",
+        r"(\B[+-])?(\d+\.\d*|\d*\.\d+|\d+)([eE]-?\d*\.?\d*)?j?([pnumkMGT])?",
+    )
     def NUMBER(self, t):
         if re.match(".*[pnumkMGT]$", t.value):
             t.value = t.value.replace("p", "e-12")
@@ -450,6 +451,14 @@ class _KatInstructionLEX(Lexer):
                 t.value = int(t.value)
         return t
 
+    @_(r"-")
+    def MINUS(self, t):
+        return t
+
+    @_(r"\+")
+    def PLUS(self, t):
+        return t
+
     @_(r"[a-zA-Z_][a-zA-Z0-9_.]*\*?", "inf")
     def STRING(self, t):
         if t.value == "inf":