// number
// integer
// rational
// string
// variable
// '(' Expr ')'
// If the value is a string, value.Expr is nil.
func (p *Parser) number(tok scan.Token) (expr value.Expr, str string) {
var err error
text := tok.Text
switch tok.Type {
case scan.Identifier:
expr = p.variable(text)
case scan.String:
str = value.ParseString(text)
case scan.Number, scan.Rational:
expr, err = value.Parse(p.context.Config(), text)
case scan.LeftParen:
expr = p.expr(p.next())
tok := p.next()
if tok.Type != scan.RightParen {
p.errorf("expected right paren, found %s", tok)
}
}
if err != nil {
p.errorf("%s: %s", text, err)
}
return expr, str
}
// getString returns the value of the string that must be next in the input.
func (p *Parser) getString() string {
return value.ParseString(p.need(scan.String).Text)
}