From 75793e4bdf65129a7158bf0c541a7528e1733856 Mon Sep 17 00:00:00 2001
From: Jonathan Cornaz <jonathan.cornaz@gmail.com>
Date: Sun, 11 Sep 2022 10:01:53 +0200
Subject: [PATCH] feat: ignore unknown directives

---
 src/directive.rs                  | 51 ++++++++++++++++++++++++++++---
 src/lib.rs                        |  5 ++-
 tests/examples/comments.beancount |  5 +++
 3 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/src/directive.rs b/src/directive.rs
index 822edfc..154b007 100644
--- a/src/directive.rs
+++ b/src/directive.rs
@@ -1,4 +1,11 @@
-use nom::{character::complete::space1, combinator::map, sequence::separated_pair, IResult};
+use nom::{
+    branch::alt,
+    bytes::complete::tag,
+    character::complete::{line_ending, not_line_ending, one_of, space1},
+    combinator::{map, not, opt, value},
+    sequence::{separated_pair, tuple},
+    IResult,
+};
 
 use crate::{
     date::date,
@@ -12,21 +19,57 @@ pub enum Directive<'a> {
     Transaction(Transaction<'a>),
 }
 
-pub(crate) fn directive(input: &str) -> IResult<&str, (Date, Directive<'_>)> {
-    separated_pair(date, space1, map(transaction, Directive::Transaction))(input)
+pub(crate) fn directive(input: &str) -> IResult<&str, (Date, Option<Directive<'_>>)> {
+    separated_pair(
+        date,
+        space1,
+        alt((
+            map(map(transaction, Directive::Transaction), Some),
+            value(
+                None,
+                tuple((
+                    not(tag("txn")),
+                    not(one_of("*!")),
+                    not_line_ending,
+                    opt(line_ending),
+                )),
+            ),
+        )),
+    )(input)
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
+    use rstest::rstest;
 
     #[test]
     fn transaction() {
         let input = r#"2022-09-10 txn "My transaction""#;
         let (_, (date, directive)) = directive(input).expect("should successfully parse directive");
         assert_eq!(date, Date::new(2022, 9, 10));
-        match directive {
+        match directive.expect("should recognize the directive") {
             Directive::Transaction(trx) => assert_eq!(trx.narration(), Some("My transaction")),
         }
     }
+
+    #[rstest]
+    #[case("2022-09-11 whatisthis \"hello\"", "")]
+    #[case("2022-09-11 whatisthis \"hello\"\ntest", "test")]
+    fn unkown_directive(#[case] input: &str, #[case] expected_rest: &str) {
+        let (rest, _) = directive(input).expect("should successfully parse the directive");
+        assert_eq!(rest, expected_rest);
+    }
+
+    #[rstest]
+    fn invalid(
+        #[values(
+            "2022-09-11 txn that is incorrect",
+            "2022-09-11 * that is incorrect",
+            "2022-09-11 ! that is incorrect"
+        )]
+        input: &str,
+    ) {
+        assert!(directive(input).is_err());
+    }
 }
diff --git a/src/lib.rs b/src/lib.rs
index aea2c49..bf438dd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -57,5 +57,8 @@ impl<'a> Iterator for Parser<'a> {
 }
 
 fn next(input: &str) -> IResult<&str, Option<(Date, Directive<'_>)>> {
-    alt((map(directive, Some), value(None, comment_line)))(input)
+    alt((
+        map(directive, |(date, directive)| directive.map(|d| (date, d))),
+        value(None, comment_line),
+    ))(input)
 }
diff --git a/tests/examples/comments.beancount b/tests/examples/comments.beancount
index c0dc17b..ef0d57c 100644
--- a/tests/examples/comments.beancount
+++ b/tests/examples/comments.beancount
@@ -1,8 +1,13 @@
 * Banking
 ** Bank of America
 
+2003-01-05 open Assets:US:BofA:Checking
+2003-01-05 open Assets:US:BofA:Savings
+
 ;; Transactions follow …
 
 ** TD Bank
 
+2006-03-15 open Assets:US:TD:Cash
+
 ;; More transactions follow …