Semantically check function calls

Previously most checking of function calls was done in kernel,
but move this to the semantic pass. Also change the parser so it
doesn't convert a primitive function call to cast and instead lets
the semantic pass do this.

Closes #4593

compiler/kernel/expr.go

@@ -282,55 +282,9 @@ func (b *Builder) compileAssignment(node *dag.Assignment) (expr.Assignment, erro
 	return expr.Assignment{LHS: lhs, RHS: rhs}, err
 }
 
-func shaperOps(name string) expr.ShaperTransform {
-	switch name {
-	case "cast":
-		return expr.Cast
-	case "crop":
-		return expr.Crop
-	case "fill":
-		return expr.Fill
-	case "fit":
-		return expr.Crop | expr.Fill
-	case "order":
-		return expr.Order
-	case "shape":
-		return expr.Cast | expr.Fill | expr.Order
-	default:
-		return 0
-	}
-
-}
-
-func isShaperFunc(name string) bool {
-	return shaperOps(name) != 0
-}
-
-func (b *Builder) compileShaper(node dag.Call) (expr.Evaluator, error) {
-	args := node.Args
-	if len(args) == 1 {
-		args = append([]dag.Expr{&dag.This{Kind: "This"}}, args...)
-	}
-	if len(args) < 2 {
-		return nil, function.ErrTooFewArgs
-	}
-	if len(args) > 2 {
-		return nil, function.ErrTooManyArgs
-	}
-	field, err := b.compileExpr(args[0])
-	if err != nil {
-		return nil, err
-	}
-	typExpr, err := b.compileExpr(args[1])
-	if err != nil {
-		return nil, err
-	}
-	return expr.NewShaper(b.zctx(), field, typExpr, shaperOps(node.Name))
-}
-
 func (b *Builder) compileCall(call dag.Call) (expr.Evaluator, error) {
-	if isShaperFunc(call.Name) {
-		return b.compileShaper(call)
+	if tf := expr.NewShaperTransform(call.Name); tf != 0 {
+		return b.compileShaper(call, tf)
 	}
 	var path field.Path
 	// First check if call is to a user defined function, otherwise check for
@@ -355,6 +309,19 @@ func (b *Builder) compileCall(call dag.Call) (expr.Evaluator, error) {
 	return expr.NewCall(b.zctx(), fn, exprs), nil
 }
 
+func (b *Builder) compileShaper(node dag.Call, tf expr.ShaperTransform) (expr.Evaluator, error) {
+	args := node.Args
+	field, err := b.compileExpr(args[0])
+	if err != nil {
+		return nil, err
+	}
+	typExpr, err := b.compileExpr(args[1])
+	if err != nil {
+		return nil, err
+	}
+	return expr.NewShaper(b.zctx(), field, typExpr, tf)
+}
+
 func (b *Builder) compileExprs(in []dag.Expr) ([]expr.Evaluator, error) {
 	var exprs []expr.Evaluator
 	for _, e := range in {

compiler/parser/parser.es.js

@@ -8365,7 +8365,7 @@ function peg$parse(input, options) {
     var s0, s1, s2, s3, s4, s5, s6, s7;
 
     s0 = peg$currPos;
-    s1 = peg$parseCastType();
+    s1 = peg$parseTypeLiteral();
     if (s1 !== peg$FAILED) {
       s2 = peg$parse__();
       if (s2 !== peg$FAILED) {
@@ -11595,23 +11595,6 @@ function peg$parse(input, options) {
     return s0;
   }
 
-  function peg$parseCastType() {
-    var s0, s1;
-
-    s0 = peg$parseTypeLiteral();
-    if (s0 === peg$FAILED) {
-      s0 = peg$currPos;
-      s1 = peg$parsePrimitiveType();
-      if (s1 !== peg$FAILED) {
-        peg$savedPos = s0;
-        s1 = peg$c404(s1);
-      }
-      s0 = s1;
-    }
-
-    return s0;
-  }
-
   function peg$parseType() {
     var s0;