Added all source files

parser.go

@@ -0,0 +1,76 @@
+// parser.go
+package expr
+
+import (
+	"fmt"
+)
+
+//-------- parser
+
+type parser struct {
+	ctx exprContext
+}
+
+func NewParser(ctx exprContext) (p *parser) {
+	p = &parser{
+		ctx: ctx,
+	}
+	return p
+}
+
+func (self *parser) parse(scanner *scanner, termSymbols ...Symbol) (tree *ast, err error) {
+	tree = NewAst()
+	firstToken := true
+	for tk := scanner.Next(); err == nil && tk != nil && !tk.IsTerm(termSymbols); tk = scanner.Next() {
+		if tk.Sym == SymComment {
+			continue
+		}
+
+		//fmt.Println("Token:", tk)
+		if firstToken && (tk.Sym == SymMinus || tk.Sym == SymPlus) {
+			if tk.Sym == SymMinus {
+				tk.Sym = SymChangeSign
+			} else {
+				tk.Sym = SymUnchangeSign
+			}
+		}
+		firstToken = false
+		if tk.Sym == 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
+			}
+			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 {
+					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 {
+			err = tree.addToken(tk)
+		}
+	}
+	return
+}