From f4e8fb7892c74dbc344de0e0d75fc0a51a7f5bb8 Mon Sep 17 00:00:00 2001
From: sam schick <github@schicksw.mozmail.com>
Date: Sat, 15 Apr 2023 15:07:47 -0400
Subject: [PATCH] added parsing of balance assertions

---
 grammar/ledger.ne    | 21 +++++++++++++--------
 tests/nearly.test.ts | 34 ++++++++++++++++++++++++++++++++++
 tests/parser.test.ts |  2 ++
 3 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/grammar/ledger.ne b/grammar/ledger.ne
index 6d264d7..6107b6e 100644
--- a/grammar/ledger.ne
+++ b/grammar/ledger.ne
@@ -1,12 +1,15 @@
 @preprocessor typescript
 
+### Partially supported ###
+# Transactions
+# - Balance assertions (https://www.ledger-cli.org/3.0/doc/ledger3.html#Balance-assertions)
+#   - parsed but ignored in output
 ### Not supported ###
 #
 # Transactions:
 # - Metadata (https://www.ledger-cli.org/3.0/doc/ledger3.html#Metadata)
 # - Virtual postings (https://www.ledger-cli.org/3.0/doc/ledger3.html#Virtual-postings)
 # - Expression amounts (https://www.ledger-cli.org/3.0/doc/ledger3.html#Expression-amounts)
-# - Balance assertions (https://www.ledger-cli.org/3.0/doc/ledger3.html#Balance-assertions)
 # - Balance assignments (https://www.ledger-cli.org/3.0/doc/ledger3.html#Balance-assignments)
 # - Commodities (https://www.ledger-cli.org/3.0/doc/ledger3.html#Commodity-prices)
 #
@@ -41,6 +44,7 @@
         currency: /[$£₤€₿₹¥￥₩Р]/, // Note: Р != P
         reconciled: /[!*]/,
         comment: { match: /[;#|][^\n]+/, value: (s:string) => s.slice(1).trim() },
+        assertion: {match: /==?\*?/},
         account: { match: /[^$£₤€₿₹¥￥₩Р;#|\n]+/, value: (s:string) => s.trim() },
       },
       alias: {
@@ -81,20 +85,21 @@ expenselines ->
   | expenselines %newline expenseline             {% ([rest,,l]) => { return [rest,l].flat(1) } %}
 
 expenseline ->
-    %ws:+ reconciled:? %account amount:? %ws:* %comment:?
+    %ws:+ reconciled:? %account amount:? balance:? %ws:* %comment:?
                                                   {%
-                                                    function(d) {
+                                                    function([,r,acct,amt,_ba,,cmt]) {
                                                       return {
-                                                        reconcile: d[1] || '',
-                                                        account: d[2].value,
-                                                        currency: d[3]?.currency,
-                                                        amount: d[3]?.amount,
-                                                        comment: d[5]?.value,
+                                                        reconcile: r || '',
+                                                        account: acct.value,
+                                                        currency: amt?.currency,
+                                                        amount: amt?.amount,
+                                                        comment: cmt?.value,
                                                       }
                                                     }
                                                   %}
   | %ws:+ %comment                                {% ([,c]) => { return {comment: c.value} } %}
 
+balance -> %ws:* %assertion %ws:+ amount                      {% (d) => {return {}} %}
 reconciled -> %reconciled %ws:+                   {% ([r,]) => r.value %}
 alias -> "alias" %account %equal %account         {% ([,l,,r]) => { return { blockLine: l.line, left: l.value, right: r.value } } %}
 amount -> %currency %number                       {% ([c,a]) => { return {currency: c.value, amount: parseFloat(a.value)} } %}
diff --git a/tests/nearly.test.ts b/tests/nearly.test.ts
index 919152e..2629bde 100644
--- a/tests/nearly.test.ts
+++ b/tests/nearly.test.ts
@@ -6,6 +6,8 @@ beforeEach(() => {
   parser = new Parser(Grammar.fromCompiled(grammar));
 });
 
+const ASSERTIONS = ['=', '=*', '==', '==*']
+
 describe('parsing multiple blocks', () => {
   test('when there are not newlines separating blocks', () => {
     parser.feed('; This is a comment\n');
@@ -299,4 +301,36 @@ describe('parsing a transaction', () => {
       ],
     ]);
   });
+  test.each(ASSERTIONS)('when there is a  "%s" balance assertion', (assertion) => {
+    parser.feed('2018-04-03 Half Price Books\n');
+    parser.feed('    Expenses:Books   $300\n');
+    parser.feed(`    Assets:Checking  $300 ${assertion} $300`);
+
+    expect(parser.results).toEqual([
+      [
+        {
+          type: 'tx',
+          blockLine: 1,
+          value: {
+            date: '2018-04-03',
+            payee: 'Half Price Books',
+            expenselines: [
+              {
+                amount: 300,
+                currency: '$',
+                account: 'Expenses:Books',
+                reconcile: '',
+              },
+              {
+                amount: 300,
+                currency: '$',
+                account: 'Assets:Checking',
+                reconcile: '',
+              },
+            ],
+          },
+        },
+      ],
+    ]);
+  });
 });
diff --git a/tests/parser.test.ts b/tests/parser.test.ts
index 645fa56..6417f39 100644
--- a/tests/parser.test.ts
+++ b/tests/parser.test.ts
@@ -875,6 +875,8 @@ alias c=Credit
         ],
       },
     };
+    
+    expect(txCache.parsingErrors).toHaveLength(0);
     expect(txCache.transactions).toHaveLength(1);
     expect(txCache.transactions[0]).toEqual(expected);
     expect(txCache.payees).toEqual(['Costco']);