Merge pull request #4 from sojidotai/feat/dollar-query-params

feat: Add an asyncpg compatible query params implementation

sqlbind/__init__.py

@@ -701,6 +701,14 @@ def compile(self, expr: str, params: t.Sequence[t.Any]) -> str:
         return expr.format(*(f'%({it})s' for it in names))
 
 
+class DollarQueryParams(ListQueryParams):
+    """QueryParams implementation for format ($1, $2, ...) parameter style"""
+
+    def compile(self, expr: str, params: t.Sequence[t.Any]) -> str:
+        start = self.add(params) + 1
+        return expr.format(*(f"${i}" for i, _ in enumerate(params, start)))
+
+
 class BaseDialect:
     """Dialect compatible with most of backends"""
 
@@ -797,6 +805,16 @@ def default_format() -> QueryParams:
         """
         return FormatQueryParams(BaseDialect)
 
+    @staticmethod
+    def default_dollar() -> QueryParams:
+        """Uses dollar params ($1, $2, ...) as placeholders.
+        Backend examples: asyncpg
+        >>> q = Dialect.default_dollar()
+        >>> f'field = {q/20}'
+        'field = $1'
+        """
+        return DollarQueryParams(BaseDialect)
+
     @staticmethod
     def sqlite() -> QueryParams:
         """Uses sqlite dialect and renders binds with qmark (?) placeholders"""

tests/test_sqlbind.py

@@ -38,6 +38,13 @@ def test_pyformat():
     assert q == {'p0': 10, 'p1': 20}
 
 
+def test_dollar():
+    q = s.Dialect.default_dollar()
+    assert q("field1 = {}", 10) == "field1 = $1"
+    assert q("field2 = {}", 20) == "field2 = $2"
+    assert q == [10, 20]
+
+
 def test_conditions():
     q = s.Dialect.default()