Add @if with equality comparison

scone/head/grammar/scoml.tx

@@ -28,7 +28,7 @@ SubBlock[ws=' \t']:
 Directive:
   UserDirective | SousDirective | ForDirective | ImportDirective |
   RecipeEdgeDirective | ResourceEdgeDirective | ListenEdgeDirective |
-  IfSetDirective
+  IfSetDirective | IfCondDirective
 ;
 
 UserDirective[ws=' \t']:
@@ -58,6 +58,10 @@ IfSetDirective[ws=' \t']:
   '@ifSet' variable=DottedIdString /\n/+
 ;
 
+IfCondDirective[ws=' \t']:
+  '@if' variable=DottedIdString operator='=' other_value=ValueExpr /\n/+
+;
+
 ResourceEdgeDirectiveKind:
   '@needs' | '@wants' | '@provides'
 ;

scone/head/menu_reader.py

@@ -94,10 +94,28 @@ class IfSetDirective(IfDirective):
     check_variable: str
 
     def condition_true(self, vars: Variables) -> bool:
-        print(f"isset? {self.check_variable} {vars.has_dotted(self.check_variable)}")
         return vars.has_dotted(self.check_variable)
 
 
+@attr.s(auto_attribs=True)
+class IfCondDirective(IfDirective):
+    # Name of the variable
+    variable: str
+
+    # The operator that is used
+    operator: str
+
+    # The other value to check for equality against
+    other_value: str
+
+    def condition_true(self, vars: Variables) -> bool:
+        if self.operator == "=":
+            value = vars.get_dotted(self.variable)
+            return value == self.other_value
+        else:
+            raise NotImplementedError(f"operator {self.operator} not understood.")
+
+
 @attr.s(auto_attribs=True)
 class RecipeEdgeDirective:
     # "after" or "before"
@@ -154,7 +172,7 @@ class MenuRecipe:
 
     user_directive: Optional[str] = None
     sous_directive: Optional[str] = None
-    control_directives: List[ForDirective] = attr.ib(factory=list)
+    control_directives: List[ControlDirective] = attr.ib(factory=list)
     recipe_edges: List[RecipeEdgeDirective] = attr.ib(factory=list)
     resource_edges: List[ResourceEdgeDirective] = attr.ib(factory=list)
     listen_edges: List[ListenEdgeDirective] = attr.ib(factory=list)
@@ -233,6 +251,13 @@ def convert_textx_recipe(txrecipe_or_subblock, parent: Optional[MenuBlock]):
                 var = directive.variable
                 assert isinstance(var, str)
                 recipe.control_directives.append(IfSetDirective(var))
+            elif isinstance(directive, scoml_classes["IfCondDirective"]):
+                var = directive.variable
+                op = directive.operator
+                other_value = convert_textx_value(directive.other_value)
+                assert isinstance(var, str)
+                assert isinstance(op, str)
+                recipe.control_directives.append(IfCondDirective(var, op, other_value))
             else:
                 raise ValueError(f"Unknown directive {directive}")