1// pest. The Elegant Parser
2// Copyright (c) 2018 Dragoș Tiselice
3//
4// Licensed under the Apache License, Version 2.0
5// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
6// license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
7// option. All files in the project carrying such notice may not be copied,
8// modified, or distributed except according to those terms.
9
10use crate::ast::*;
11
12pub fn concatenate(rule: Rule) -> Rule {
13 let Rule { name: String, ty: RuleType, expr: Expr } = rule;
14 Rule {
15 name,
16 ty,
17 expr: expr.map_bottom_up(|expr: Expr| {
18 if ty == RuleType::Atomic {
19 match expr {
20 Expr::Seq(lhs: Box, rhs: Box) => match (*lhs, *rhs) {
21 (Expr::Str(lhs: String), Expr::Str(rhs: String)) => Expr::Str(lhs + &rhs),
22 (Expr::Insens(lhs: String), Expr::Insens(rhs: String)) => Expr::Insens(lhs + &rhs),
23 (lhs: Expr, rhs: Expr) => Expr::Seq(Box::new(lhs), Box::new(rhs)),
24 },
25 expr: Expr => expr,
26 }
27 } else {
28 expr
29 }
30 }),
31 }
32}
33