3 files changed, 55 insertions, 5 deletions
diff --git a/requirements/catalogue/req-030.md b/requirements/catalogue/req-030.md
index 2cb1bdd..e09a281 100644
--- a/requirements/catalogue/req-030.md
+++ b/requirements/catalogue/req-030.md
@@ -15,10 +15,12 @@ Inputs:
 5. Let `is_up_to_date` be the result of the procedure,
    `is_bucket_balance_up_to_date(bucket)`, as described in req-035.
 6. If `is_up_to_date = TRUE`, then return `bucket.balance`.
-7. Let `transaction_sum` be the sum over the property, `amount`, of all
+7. Carry out the procedure, `update_bucket_drips(bucket)`, as described in
+   req-037.
+8. Let `transaction_sum` be the sum over the property, `amount`, of all
    transactions `t` such that `t.bucket_id = bucket.id`.
-8. Let `drip_sum` be the sum over the property, `amount`, of all drips `d` such
+9.  Let `drip_sum` be the sum over the property, `amount`, of all drips `d` such
    that `d.bucket_id = bucket.id`.
-9. Return `drip_sum - transaction_sum`.
+10. Return `drip_sum - transaction_sum`.
 
 Source: req-029
diff --git a/requirements/catalogue/req-035.md b/requirements/catalogue/req-035.md
index 0dc9aaf..15b797b 100644
--- a/requirements/catalogue/req-035.md
+++ b/requirements/catalogue/req-035.md
@@ -14,8 +14,8 @@ Inputs:
 3. Let `drip_id` be the part of `cache_key` before the `:`.
 4. If there is no drip with the ID, `drip_id`, then return FALSE.
 5. Let `drip` be the drip with the ID, `drip_id`.
-6. If there is a drip, `drip_2`, such that `drip_2.date > drip.date` and
-   `drip.bucket_id = bucket.id`, then return FALSE.
+6. If there is a drip, `drip_2`, such that `drip_2.timestamp > drip.timestamp`
+   and `drip.bucket_id = bucket.id`, then return FALSE.
 7. Let `transaction_id` be the part of `cache_key` after the `:`.
 8. If there is no transaction with the ID, `transaction_id`, then return FALSE.
 9. Let `transaction` be the transaction with the ID, `transaction_id`.
diff --git a/requirements/catalogue/req-037.md b/requirements/catalogue/req-037.md
new file mode 100644
index 0000000..0d27984
--- /dev/null
+++ b/requirements/catalogue/req-037.md
@@ -0,0 +1,48 @@
+# req-037
+
+Schist must implement the procedure, described below as
+`update_budget_drips_for_bucket`.
+
+## update_budget_drips_for_bucket
+
+Inputs:
+
+- A bucket, `bucket`
+
+1. For each pipe `p` such that `p.bucket_id = bucket.id`, carry out the
+   sub-procedure, `update_budget_drips_for_pipe(pipe)`, as described below.
+
+## update_budget_drips_for_pipe
+
+Inputs:
+
+- A pipe, `pipe`
+
+1. Let `prev_drip` be a drip `d` with a most recent value for the property
+   `date` such that `d.pipe_id = pipe.id`
+2. For each calendar date `d` in the range `(prev_drip.date, today]`, insert
+   a new drip for `pipe`:
+   - `bucket_id`: `pipe.bucket_id`
+   - `pipe_id`: `pipe.id`
+   - `date`: `d`
+   - `amount`: the result of the sub-procedure, `pipe_amount_for_day(pipe, d)`
+     as described below
+   - `timestamp`: now as a Unix timestamp
+
+## pipe_amount_for_date
+
+Inputs:
+
+- A pipe, `pipe`
+- A calendar date, `date`
+
+1. If `pipe.period` is `day`, return `pipe.amount`.
+2. If `pipe.period` is `week`, return `pipe.amount ÷ 7`.
+3. Let `days_in_month` be the number of days in the month to which `date`
+   belongs.
+4. If `pipe.period` is `month`, return `pipe.amount ÷ days_in_month`.
+5. Let `days_in_year` be the number of days in the year to which `date` belongs.
+6. If `period` is not `year`, panic.
+7. Return `pipe.amount ÷ days_in_year`.
+
+Source: req-030
+\ No newline at end of file