Merge pull request #164 from d409f19/limited-exprs

Disallow function calls and neighbourhoods in constant declarations
d409f19 · May 16, 2019 · d359346 · d359346
2 parents 0b3d759 + 02d8648
commit d359346
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Showing 4 changed files with 50 additions and 7 deletions.
diff --git a/compiler/src/main/kotlin/visitors/sanitychecker.kt b/compiler/src/main/kotlin/visitors/sanitychecker.kt
@@ -22,9 +22,11 @@ class DimensionsError(ctx: SourceContext, description: String) : CompileError(ct
  */
 class SanityChecker : BaseASTVisitor() {
 
-    var inAFunction = false
-    var dimensions: Int = 0
-    var worldHasEdge = false
+    private var inAFunction = false
+    private var inAState = false
+    private var numberOfStates = 0
+    private var dimensions: Int = 0
+    private var worldHasEdge = false
 
     override fun visit(node: WorldNode) {
         dimensions = node.dimensions.size
@@ -86,9 +88,6 @@ class SanityChecker : BaseASTVisitor() {
             ErrorLogger += SanityError(node.ctx, "Become statements cannot be in functions")
     }
 
-    var inAState = false
-    var numberOfStates = 0
-
     override fun visit(node: StateDecl) {
         inAState = true
         super.visit(node)

diff --git a/compiler/src/main/kotlin/visitors/typechecker.kt b/compiler/src/main/kotlin/visitors/typechecker.kt
@@ -14,8 +14,11 @@ class TypeError(ctx: SourceContext, description: String) : CompileError(ctx, des
  * Synthesizes types by moving them up the abstract syntax tree according to the type rules, and check that there is no violation of the type rules
  */
 class TypeChecker(symbolTable: Table) : ScopedASTVisitor(symbolTable = symbolTable) {
+
     private var expectedReturn: Type? = null
     private var isOuterArray = true
+    // Constants are limited. Function calls and neighbourhoods are not allowed in limited expressions
+    private var inLimitedConstExpr = false
 
     override fun visit(node: WorldNode) {
         node.dimensions.forEach { visit(it) }
@@ -351,7 +354,12 @@ class TypeChecker(symbolTable: Table) : ScopedASTVisitor(symbolTable = symbolTab
             node.setType(
                 when (decl) {
                     is StateDecl -> StateType
-                    is NeighbourhoodDecl -> LocalNeighbourhoodType
+                    is NeighbourhoodDecl -> {
+                        if (inLimitedConstExpr) {
+                            ErrorLogger += TypeError(node.ctx, "Neighbourhoods are not allowed in constant declarations.")
+                        }
+                        LocalNeighbourhoodType
+                    }
                     is AssignStmt -> decl.expr.getType()
                     is ConstDecl -> decl.expr.getType()
                     is FunctionArgument -> decl.type
@@ -533,6 +541,10 @@ class TypeChecker(symbolTable: Table) : ScopedASTVisitor(symbolTable = symbolTab
     override fun visit(node: FuncCallExpr) {
         super.visit(node)
 
+        if (inLimitedConstExpr) {
+            ErrorLogger += TypeError(node.ctx, "Function calls are not allowed in constant declarations.")
+        }
+
         val funcDecl = symbolTableSession.getSymbol(node.ident)
 
         // If node is not a function, register error and continue type-checking
@@ -594,8 +606,10 @@ class TypeChecker(symbolTable: Table) : ScopedASTVisitor(symbolTable = symbolTab
     }
 
     override fun visit(node: ConstDecl) {
+        inLimitedConstExpr = true
         super.visit(node)
         node.type = node.expr.getType()
+        inLimitedConstExpr = false
     }
 
     override fun visit(node: AssignStmt) {

diff --git a/compiler/src/main/resources/non-compiling-programs/const-fun.cell b/compiler/src/main/resources/non-compiling-programs/const-fun.cell
@@ -0,0 +1,15 @@
+world {
+    size = 100 [wrap], 100 [wrap];
+    tickrate = 1;
+    cellsize = 5;
+}
+
+const c = 20 + foo(i)
+
+state alive (0, 0, 0) {
+
+}
+
+function foo(int i) int {
+    return i + i;
+}
diff --git a/compiler/src/main/resources/non-compiling-programs/const-ngbh.cell b/compiler/src/main/resources/non-compiling-programs/const-ngbh.cell
@@ -0,0 +1,15 @@
+world {
+    size = 100 [wrap], 100 [wrap];
+    tickrate = 1;
+    cellsize = 5;
+}
+
+neighbourhood nei {
+    (1, 0)
+}
+
+const c = alive == nei[0];
+
+state alive (0, 0, 0) {
+
+}