# `PgFlow.Sql.Splitter`
[🔗](https://github.com/agoodway/pgflow/blob/v0.1.0/lib/pgflow/sql/splitter.ex#L1)

Splits a raw PostgreSQL script into individual top-level statements.

Needed because `Ecto.Migration.execute/1` dispatches through Postgrex
prepared-statement protocol, which rejects multi-command input with
`42601 syntax_error`. EctoEvolver runs each `--SPLIT--`-delimited chunk
as a single `execute/1` call, so the vendored SQL has to be pre-split
one-statement-per-chunk.

## State machine

Top-level splitting ignores semicolons inside:

  * single-quoted strings (`'...'` with `''` escape)
  * double-quoted identifiers (`"..."` with `""` escape)
  * dollar-quoted bodies (`$$ ... $$` or `$tag$ ... $tag$`)
  * single-line comments (`-- ...\n`)
  * block comments (`/* ... */`, non-nested per Postgres grammar)

Only a `;` seen in the top-level state ends a statement. Leading
whitespace and trailing whitespace on each statement are stripped; empty
chunks (whitespace / comments only) are discarded.

## Output shape

    iex> PgFlow.Sql.Splitter.split("SELECT 1; SELECT 2;")
    ["SELECT 1", "SELECT 2"]

    iex> PgFlow.Sql.Splitter.split("-- comment\nSELECT 1;")
    ["-- comment\nSELECT 1"]

Returns a list of trimmed statement strings in source order.

# `join`

```elixir
@spec join([String.t()]) :: String.t()
```

Join statements back into a single script with `--SPLIT--` markers.

# `split`

```elixir
@spec split(binary()) :: [String.t()]
```

Split a SQL script into top-level statements.

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*Consult [api-reference.md](api-reference.md) for complete listing*