implement Eval

Author: itchyny

ast/node.go

@@ -342,6 +342,17 @@ type Throw struct {
 func (f *Throw) Pos() Pos { return f.Throw }
 func (f *Throw) Cmd() Cmd { return *f.ExArg.Cmd }
 
+// vimlparser: EVAL .ea .left
+// :eval {Expr}
+type Eval struct {
+	Eval  Pos   // position of starting the :eval
+	ExArg ExArg // Ex command arg
+	Expr  Expr
+}
+
+func (f *Eval) Pos() Pos { return f.Eval }
+func (f *Eval) Cmd() Cmd { return *f.ExArg.Cmd }
+
 // vimlparser: ECHO .ea .list
 // vimlparser: ECHON .ea .list
 // vimlparser: ECHOMSG .ea .list
@@ -584,6 +595,7 @@ func (*Let) stmtNode()        {}
 func (*LockVar) stmtNode()    {}
 func (*Return) stmtNode()     {}
 func (*Throw) stmtNode()      {}
+func (*Eval) stmtNode()       {}
 func (*Try) stmtNode()        {}
 func (*UnLet) stmtNode()      {}
 func (*UnLockVar) stmtNode()  {}

ast/walk.go

@@ -135,6 +135,9 @@ func Walk(v Visitor, node Node) {
 	case *Throw:
 		Walk(v, n.Expr)
 
+	case *Eval:
+		Walk(v, n.Expr)
+
 	case *EchoCmd:
 		walkExprList(v, n.Exprs)
 

compiler/compiler.go

@@ -129,6 +129,8 @@ func (c *Compiler) compileExcommand(node ast.ExCommand) error {
 		c.compileTry(n)
 	case *ast.Throw:
 		c.compileThrow(n)
+	case *ast.Eval:
+		c.compileEval(n)
 	case *ast.EchoCmd:
 		c.compileEchocmd(n)
 	case *ast.Echohl:
@@ -332,6 +334,11 @@ func (c *Compiler) compileThrow(node *ast.Throw) {
 	c.fprintln("(%s %s)", cmd, c.compileExpr(node.Expr))
 }
 
+func (c *Compiler) compileEval(node *ast.Eval) {
+	cmd := node.Cmd().Name
+	c.fprintln("(%s %s)", cmd, c.compileExpr(node.Expr))
+}
+
 func (c *Compiler) compileEchocmd(node *ast.EchoCmd) {
 	cmd := node.Cmd().Name
 	exprs := make([]string, 0, len(node.Exprs))

go/export.go

@@ -275,6 +275,13 @@ func newAstNode(n *VimNode, filename string) ast.Node {
 			Expr:  newExprNode(n.left, filename),
 		}
 
+	case NODE_EVAL:
+		return &ast.Eval{
+			Eval:  pos,
+			ExArg: newExArg(*n.ea, filename),
+			Expr:  newExprNode(n.left, filename),
+		}
+
 	case NODE_ECHO, NODE_ECHON, NODE_ECHOMSG, NODE_ECHOERR:
 		return &ast.EchoCmd{
 			Start:   pos,