check assignment targets

il65/examples/test.ill

@@ -80,7 +80,6 @@
   equalQQ = foo(33)
   equalQQ = main.foo(33)
   XY = hopla*2+hopla1
-  A = "derp" * %000100
 
   byte equalWW = 4==4
   const byte equalWW2 = (4+hopla)>0
@@ -123,6 +122,14 @@
 
   main.foo(1,2,3)
 
+  sub start () -> () {
+    word dinges = 0
+    dinges=round(blerp1)
+    A=round(blerp1)
+    return
+  }
+
+
 mega:
 	X += 1
 cool:

il65/src/il65/ast/AST.kt

@@ -17,6 +17,8 @@ enum class DataType {
     STR_P,
     STR_S,
     STR_PS
+
+    // TODO arrays (of byte, word)  and matrix (of byte) should have their own datatype as well?
 }
 
 enum class Register {
@@ -25,12 +27,7 @@ enum class Register {
     Y,
     AX,
     AY,
-    XY,
+    XY
-    PC,
-    PI,
-    PZ,
-    PN,
-    PV
 }
 
 enum class Statusflag {
@@ -168,6 +165,12 @@ interface IAstProcessor {
     fun process(literalValue: LiteralValue): LiteralValue {
         return literalValue
     }
+
+    fun process(assignment: Assignment): IStatement {
+        assignment.target = assignment.target.process(this)
+        assignment.value = assignment.value.process(this)
+        return assignment
+    }
 }
 
 
@@ -362,7 +365,7 @@ private class GlobalNamespace(override val name: String,
                               override var statements: MutableList<IStatement>,
                               override val position: Position?) : INameScope {
 
-    private val scopedNamesUsed: MutableSet<String> = mutableSetOf("main")      // main is always used
+    private val scopedNamesUsed: MutableSet<String> = mutableSetOf("main", "main.start")      // main and main.start are always used
 
     override fun usedNames(): Set<String>  = scopedNamesUsed
 
@@ -515,7 +518,7 @@ class VarDecl(val type: VarDeclType,
 
     override fun process(processor: IAstProcessor) = processor.process(this)
 
-    val isScalar = arrayspec==null
+    val isScalar = arrayspec==null      // TODO replace with actual array/matrix datatype itself?
     val isArray = arrayspec!=null && arrayspec.y==null
     val isMatrix = arrayspec?.y != null
     val scopedname: List<String> by lazy { makeScopedName(name) }
@@ -543,11 +546,7 @@ class Assignment(var target: AssignTarget, val aug_op : String?, var value: IExp
         value.linkParents(this)
     }
 
-    override fun process(processor: IAstProcessor): IStatement {
+    override fun process(processor: IAstProcessor) = processor.process(this)
-        target = target.process(processor)
-        value = value.process(processor)
-        return this
-    }
 }
 
 data class AssignTarget(val register: Register?, val identifier: IdentifierReference?) : Node {
@@ -560,6 +559,18 @@ data class AssignTarget(val register: Register?, val identifier: IdentifierRefer
     }
 
     fun process(processor: IAstProcessor) = this
+
+    fun determineDatatype(namespace: INameScope, stmt: IStatement): DataType {
+        if(register!=null)
+            return when(register){
+                Register.A, Register.X, Register.Y -> DataType.BYTE
+                Register.AX, Register.AY, Register.XY -> DataType.WORD
+            }
+
+        val symbol = namespace.lookup(identifier!!.nameInSource, stmt)
+        if(symbol is VarDecl) return symbol.datatype
+        throw FatalAstException("cannot determine datatype of assignment target $this")
+    }
 }
 
 
@@ -597,9 +608,8 @@ class BinaryExpression(var left: IExpression, val operator: String, var right: I
         right.linkParents(this)
     }
 
-    override fun constValue(namespace: INameScope): LiteralValue? {
+    // binary expression should actually have been optimized away into a single value, before const value was requested...
-        throw FatalAstException("binary expression should have been optimized away into a single value, before const value was requested (this error is often caused by another) pos=$position")
+    override fun constValue(namespace: INameScope): LiteralValue? = null
-    }
 
     override fun process(processor: IAstProcessor) = processor.process(this)
     override fun referencesIdentifier(name: String) = left.referencesIdentifier(name) || right.referencesIdentifier(name)
@@ -813,7 +823,7 @@ class FunctionCallStatement(override var target: IdentifierReference, override v
     override fun process(processor: IAstProcessor) = processor.process(this)
 
     override fun toString(): String {
-        return "FunctionCall(target=$target, targetStmt=$targetStatement, pos=$position)"
+        return "FunctionCall(target=$target, pos=$position)"
     }
 }
 

il65/src/il65/ast/AstChecker.kt

@@ -41,6 +41,13 @@ class AstChecker(private val globalNamespace: INameScope, val compilerOptions: C
                     entry.value.mapTo(checkResult) { SyntaxError("directive can just occur once", it.position) }
             }
         }
+
+        // there must be a 'main' block with a 'start' subroutine for the program entry point.
+        val mainBlock = module.statements.singleOrNull { it is Block && it.name=="main" } as? Block?
+        val startSub = mainBlock?.subScopes()?.get("start")
+        if(startSub==null) {
+            checkResult.add(SyntaxError("missing program entrypoint ('start' subroutine in 'main' block)", module.position))
+        }
     }
 
     override fun process(jump: Jump): IStatement {
@@ -107,6 +114,31 @@ class AstChecker(private val globalNamespace: INameScope, val compilerOptions: C
         return subroutine
     }
 
+    /**
+     * Assignment target must be register, or a variable name
+     * for constant-value assignments, check the datatype as well
+     */
+    override fun process(assignment: Assignment): IStatement {
+        if(assignment.target.identifier!=null) {
+            val targetSymbol = globalNamespace.lookup(assignment.target.identifier!!.nameInSource, assignment)
+            if(targetSymbol !is VarDecl) {
+                checkResult.add(SyntaxError("assignment LHS must be register or variable", assignment.position))
+                return super.process(assignment)
+            } else if(targetSymbol.type==VarDeclType.CONST) {
+                checkResult.add(SyntaxError("cannot assign new value to a constant", assignment.position))
+                return super.process(assignment)
+            }
+        }
+
+        if(assignment.value is LiteralValue) {
+            val targetDatatype = assignment.target.determineDatatype(globalNamespace, assignment)
+            if(checkValueType(targetDatatype, assignment.value as LiteralValue, assignment.position)) {
+                checkValueRange(targetDatatype, assignment.value as LiteralValue, assignment.position)
+            }
+        }
+        return super.process(assignment)
+    }
+
     /**
      * Check the variable declarations (values within range etc)
      */
@@ -399,28 +431,36 @@ class AstChecker(private val globalNamespace: INameScope, val compilerOptions: C
             return false
         }
         when {
-            vardecl.isScalar -> when (vardecl.datatype) {
+            vardecl.isScalar -> checkValueType(vardecl.datatype, value, position)
-                DataType.FLOAT -> {
+            vardecl.isArray -> if(value.arrayvalue==null) return err("array value expected")
-                    if (value.floatvalue == null)
-                        return err("floating point value expected")
-                }
-                DataType.BYTE -> {
-                    if (value.intvalue == null)
-                        return err("byte integer value expected")
-                }
-                DataType.WORD -> {
-                    if (value.intvalue == null)
-                        return err("word integer value expected")
-                }
-                DataType.STR, DataType.STR_P, DataType.STR_S, DataType.STR_PS -> {
-                    if (value.strvalue == null)
-                        return err("string value expected")
-                }
-            }
-            vardecl.isArray -> if(value.arrayvalue==null)
-                return err("array value expected")
             vardecl.isMatrix -> TODO()
         }
         return true
     }
+
+    private fun checkValueType(targetType: DataType, value: LiteralValue, position: Position?) : Boolean {
+        fun err(msg: String) : Boolean {
+            checkResult.add(SyntaxError(msg, position))
+            return false
+        }
+        when(targetType) {
+            DataType.FLOAT -> {
+                if (value.floatvalue == null)
+                    return err("floating point value expected")
+            }
+            DataType.BYTE -> {
+                if (value.intvalue == null)
+                    return err("byte integer value expected")
+            }
+            DataType.WORD -> {
+                if (value.intvalue == null)
+                    return err("word integer value expected")
+            }
+            DataType.STR, DataType.STR_P, DataType.STR_S, DataType.STR_PS -> {
+                if (value.strvalue == null)
+                    return err("string value expected")
+            }
+        }
+        return true
+    }
 }