From c36c88d0fdee3aabefbac633d30bcc367d61a23f Mon Sep 17 00:00:00 2001
From: Celestino Amoroso <celestino.amoroso@gmail.com>
Date: Thu, 28 Mar 2024 08:51:02 +0100
Subject: [PATCH] Added list '[]' data type. Fix: function with no arguments

---
 operand-list.go | 35 +++++++++++++++++++
 parser.go       | 90 ++++++++++++++++++++++++++++++++++---------------
 symbol.go       |  1 +
 3 files changed, 99 insertions(+), 27 deletions(-)
 create mode 100644 operand-list.go

diff --git a/operand-list.go b/operand-list.go
new file mode 100644
index 0000000..9a52522
--- /dev/null
+++ b/operand-list.go
@@ -0,0 +1,35 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operand-list.go
+package expr
+
+// -------- list term
+func newListTerm(args []*term) *term {
+	return &term{
+		tk:       *NewToken(SymList, "[]"),
+		class:    classVar,
+		kind:     kindUnknown,
+		parent:   nil,
+		children: args,
+		position: posLeaf,
+		priority: priValue,
+		evalFunc: evalList,
+	}
+}
+
+// -------- list func
+func evalList(ctx exprContext, self *term) (v any, err error) {
+	items := make([]any, len(self.children))
+	for i, tree := range self.children {
+		var param any
+		if param, err = tree.compute(ctx); err != nil {
+			break
+		}
+		items[i] = param
+	}
+	if err == nil {
+		v = items
+	}
+	return
+}
diff --git a/parser.go b/parser.go
index 29d228f..717293c 100644
--- a/parser.go
+++ b/parser.go
@@ -21,6 +21,58 @@ func NewParser(ctx exprContext) (p *parser) {
 	return p
 }
 
+func (self *parser) parseFunction(scanner *scanner, tk *Token) (tree *term, err error) {
+	name, _ := tk.Value.(string)
+	funcObj := self.ctx.GetFuncInfo(name)
+	if funcObj == nil {
+		err = fmt.Errorf("unknown function %q", name)
+		return
+	}
+	maxArgs := funcObj.MaxArgs()
+	if maxArgs < 0 {
+		maxArgs = funcObj.MinArgs() + 10
+	}
+	args := make([]*term, 0, maxArgs)
+	lastSym := SymUnknown
+	for lastSym != SymClosedRound && lastSym != SymEos {
+		var subTree *ast
+		if subTree, err = self.parse(scanner, SymComma, SymClosedRound); err == nil {
+			if subTree.root != nil {
+				args = append(args, subTree.root)
+			}
+		} else {
+			break
+		}
+		lastSym = scanner.Previous().Sym
+	}
+	if err == nil {
+		// TODO Check arguments
+		tree = newFuncTerm(tk, args)
+	}
+	return
+}
+
+func (self *parser) parseList(scanner *scanner) (tree *term, err error) {
+	args := make([]*term, 0)
+	lastSym := SymUnknown
+	for lastSym != SymClosedSquare && lastSym != SymEos {
+		var subTree *ast
+		if subTree, err = self.parse(scanner, SymComma, SymClosedSquare); err == nil {
+			if subTree.root != nil {
+				args = append(args, subTree.root)
+			}
+		} else {
+			break
+		}
+		lastSym = scanner.Previous().Sym
+	}
+	if err == nil {
+		// TODO Check arguments
+		tree = newListTerm(args)
+	}
+	return
+}
+
 func (self *parser) parse(scanner *scanner, termSymbols ...Symbol) (tree *ast, err error) {
 	tree = NewAst()
 	firstToken := true
@@ -38,40 +90,24 @@ func (self *parser) parse(scanner *scanner, termSymbols ...Symbol) (tree *ast, e
 			}
 		}
 		firstToken = false
-		if tk.Sym == SymOpenRound {
+		switch tk.Sym {
+		case SymOpenRound:
 			var subTree *ast
 			if subTree, err = self.parse(scanner, SymClosedRound); err == nil {
 				subTree.root.priority = priValue
 				tree.addTerm(subTree.root)
 			}
-		} else if tk.Sym == SymFunction {
-			name, _ := tk.Value.(string)
-			funcObj := self.ctx.GetFuncInfo(name)
-			if funcObj == nil {
-				err = fmt.Errorf("unknown function %q", name)
-				break
+		case SymFunction:
+			var funcTerm *term
+			if funcTerm, err = self.parseFunction(scanner, tk); err == nil {
+				err = tree.addTerm(funcTerm)
 			}
-			maxArgs := funcObj.MaxArgs()
-			if maxArgs < 0 {
-				maxArgs = funcObj.MinArgs() + 10
+		case SymOpenSquare:
+			var listTerm *term
+			if listTerm, err = self.parseList(scanner); err == nil {
+				err = tree.addTerm(listTerm)
 			}
-			args := make([]*term, 0, maxArgs)
-			lastSym := SymUnknown
-			for lastSym != SymClosedRound && lastSym != SymEos {
-				var subTree *ast
-				if subTree, err = self.parse(scanner, SymComma, SymClosedRound); err == nil {
-					args = append(args, subTree.root)
-				} else {
-					break
-				}
-				lastSym = scanner.Previous().Sym
-			}
-			if err == nil {
-				// TODO Check arguments
-				t := newFuncTerm(tk, args)
-				tree.addTerm(t)
-			}
-		} else {
+		default:
 			err = tree.addToken(tk)
 		}
 	}
diff --git a/symbol.go b/symbol.go
index 95987c9..e9983b3 100644
--- a/symbol.go
+++ b/symbol.go
@@ -70,6 +70,7 @@ const (
 	SymNot
 	SymComment
 	SymFunction
+	SymList
 	// SymOpenComment                       //   0: '/*'
 	// SymClosedComment                     //   0: '*/'
 	// SymOneLineComment                    //   0: '//'