Fix Query Parser for Automated Transactions (#1)

* Add failing test for use case

TBH I don't know what I'm doing here, but this seems to fail for the
right reasons enough to reflect the parser bug here.

* Append to the ident on a closing brace ')'

When parsing the automated rule, a scanner reads the line left-to-right
char-by-char. The default behaviour is to append the char under the
cursor to some `ident` string. When the cursor is on a ')', it skips the
default handling and switches into some special handling: it tries to
test the string it's reading if it's one of the keywords it knows, to
select which type of token just got scanned. If what was scanned is not
a known token, it defaults to `token_t::TERM` and returns a new token
with the currently accumulated `ident` as a `token_t::TERM`. Issue is,
since it skipped the appending to do some custom handling, the
`token_t::TERM` will always be without its closing brace. The scanner
needs to append the character under the cursor if it's falling through
to default processing.

* fix test case

- ensure proper spacing for the posting to have an amount
- ensure the posting balances against an account
- the meaning of the number after `->` is the exit code

* undo wrong approach

* consume_next if unbalanced_braces

* how this can be extended

2 files changed, 15 insertions, 0 deletions

diff --git a/src/query.cc b/src/query.cc
index 705ba151..a157b4d1 100644
--- a/src/query.cc
+++ b/src/query.cc
@@ -36,6 +36,17 @@
 
 namespace ledger {
 
+// TODO: Extend this to handle all characters which define enclosures
+bool query_t::lexer_t::unbalanced_braces(string str) {
+  int balance = 0;
+  for (char& c : str) {
+    if (c == '(') ++balance;
+    else if (c == ')')
+      if (--balance < 0) return true;
+  }
+  return balance != 0;
+}
+
 query_t::lexer_t::token_t
 query_t::lexer_t::next_token(query_t::lexer_t::token_t::kind_t tok_context)
 {
@@ -157,6 +168,8 @@ query_t::lexer_t::next_token(query_t::lexer_t::token_t::kind_t tok_context)
         break;
 
       case ')':
+        if (unbalanced_braces(ident))
+          consume_next = true;
         if (! consume_next && tok_context == token_t::TOK_EXPR)
           goto test_ident;
         // fall through...
diff --git a/src/query.h b/src/query.h
index 20a7bc18..581c7533 100644
--- a/src/query.h
+++ b/src/query.h
@@ -231,6 +231,8 @@ public:
         token_cache = next_token(tok_context);
       return token_cache;
     }
+
+    bool unbalanced_braces(const string str);
   };
 
   enum kind_t {