Merge pull request #9 from dimacurrentai/unittests

Added a trivial unit test.

Author: dkorolev

.gitignore

@@ -1,5 +1,7 @@
 Cargo.lock
 target/
 
+.vscode/
+
 # Using the `Dockerfile.template` in the root directory now.
 Dockerfile

step05_test/code/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "pest_example"
+edition = "2024"
+
+[dependencies]
+pest = "2.7"
+pest_derive = "2.7"

step05_test/code/src/golden.txt

@@ -0,0 +1 @@
+[Pair { rule: identifier, span: Span { str: "a", start: 0, end: 1 }, inner: [Pair { rule: alpha, span: Span { str: "a", start: 0, end: 1 }, inner: [] }] }, Pair { rule: op, span: Span { str: "+", start: 2, end: 3 }, inner: [Pair { rule: plus, span: Span { str: "+", start: 2, end: 3 }, inner: [] }] }, Pair { rule: identifier, span: Span { str: "b", start: 4, end: 5 }, inner: [Pair { rule: alpha, span: Span { str: "b", start: 4, end: 5 }, inner: [] }] }, Pair { rule: identifier, span: Span { str: "a2", start: 6, end: 8 }, inner: [Pair { rule: alpha, span: Span { str: "a", start: 6, end: 7 }, inner: [] }, Pair { rule: digit, span: Span { str: "2", start: 7, end: 8 }, inner: [] }] }, Pair { rule: op, span: Span { str: "-", start: 9, end: 10 }, inner: [Pair { rule: minus, span: Span { str: "-", start: 9, end: 10 }, inner: [] }] }, Pair { rule: identifier, span: Span { str: "b2", start: 11, end: 13 }, inner: [Pair { rule: alpha, span: Span { str: "b", start: 11, end: 12 }, inner: [] }, Pair { rule: digit, span: Span { str: "2", start: 12, end: 13 }, inner: [] }] }, Pair { rule: op, span: Span { str: "+", start: 14, end: 15 }, inner: [Pair { rule: plus, span: Span { str: "+", start: 14, end: 15 }, inner: [] }] }, Pair { rule: number, span: Span { str: "42", start: 16, end: 18 }, inner: [Pair { rule: digit, span: Span { str: "4", start: 16, end: 17 }, inner: [] }, Pair { rule: digit, span: Span { str: "2", start: 17, end: 18 }, inner: [] }] }]

step05_test/code/src/grammar.pest

@@ -0,0 +1,13 @@
+alpha = { 'a'..'z' | 'A'..'Z' }
+digit = { '0'..'9' }
+
+identifier = { alpha ~ (alpha | digit)* }
+number = { digit+ }
+
+plus = { "+" }
+minus = { "-" }
+op = { plus | minus }
+
+term = _{ identifier | number | op }
+
+toplevel = _{ term ~ (" "+ ~ term)* }

step05_test/code/src/main.rs

@@ -0,0 +1,49 @@
+use pest::Parser;
+use pest::iterators::Pair;
+use pest_derive::Parser;
+
+#[derive(Parser)]
+#[grammar = "grammar.pest"]
+struct Grammar;
+
+fn traverse(token: Pair<'_, Rule>, indent: usize) {
+  let (next_indent, proceed) = match token.as_rule() {
+    // These next two lines are unnecessary, since the terms are declared as `_{ ... }`, where `_` means "silent".
+    // Rule::toplevel => (0, true),
+    // Rule::term => (0, true),
+    Rule::identifier => {
+      println!("{}S: {}", " ".repeat(indent), token.as_str());
+      (2, true)
+    }
+    Rule::number => {
+      println!("{}N: {}", " ".repeat(indent), token.as_str());
+      (0, false)
+    }
+    Rule::op => {
+      println!("{}V: {}", " ".repeat(indent), token.as_str());
+      (0, false)
+    }
+    _ => {
+      println!("{}INTERNAL {:?} {}", " ".repeat(indent), token.as_rule(), token.as_str());
+      (2, true)
+    }
+  };
+  if proceed {
+    token.into_inner().for_each(|e| traverse(e, next_indent));
+  }
+}
+
+fn main() {
+  Grammar::parse(Rule::toplevel, "a + b a2 - b2 + 42").unwrap().for_each(|e| traverse(e, 0));
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn test_parser() {
+    const GOLDEN: &str = include_str!("golden.txt");
+    assert_eq!(format!("{:?}", Grammar::parse(Rule::toplevel, "a + b a2 - b2 + 42").unwrap()), GOLDEN.trim());
+  }
+}

step05_test/run.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+set -e
+
+docker build -f ../Dockerfile.template . -t demo
+docker run --rm -t demo