nom-sql: Lowercase unquoted no-paren functions in Postgres

This is just to add some consistency to our Postgres identifier casing
approach (which is to lowercase them during parsing), so that we can
treat identifiers uniformly when converting from sqlparser-rs. This
entire approach may go away in the future, and I would rather such a
hack/special case be in nom-sql rather than in readyset-sql.

Change-Id: I288e827d4ba3a3ca9bbc2552285777a187253d5a
Reviewed-on: https://gerrit.readyset.name/c/readyset/+/9041
Reviewed-by: Johnathan Davis <jcd@readyset.io>
Tested-by: Buildkite CI

Author: mvzink

nom-sql/src/common.rs

@@ -126,31 +126,37 @@ fn delim_fx_args(
     }
 }
 
-fn function_call_without_parens(i: LocatedSpan<&[u8]>) -> NomSqlResult<&[u8], FunctionExpr> {
-    // Some functions can be called without parentheses, in both mysql and postgres
-    let (i, name) = map(
-        alt((
-            tag_no_case("now"),
-            tag_no_case("current_date"),
-            tag_no_case("current_timestamp"),
-            tag_no_case("current_time"),
-            tag_no_case("localtimestamp"),
-            tag_no_case("localtime"),
-        )),
-        |n: LocatedSpan<&[u8]>| {
-            String::from_utf8(n.to_vec())
-                .expect("Only constant string literals")
-                .into()
-        },
-    )(i)?;
-
-    Ok((
-        i,
-        FunctionExpr::Call {
-            name,
-            arguments: vec![],
-        },
-    ))
+fn function_call_without_parens(
+    dialect: Dialect,
+) -> impl Fn(LocatedSpan<&[u8]>) -> NomSqlResult<&[u8], FunctionExpr> {
+    move |i| {
+        // Some functions can be called without parentheses, in both mysql and postgres
+        let (i, name) = map(
+            alt((
+                tag_no_case("now"),
+                tag_no_case("current_date"),
+                tag_no_case("current_timestamp"),
+                tag_no_case("current_time"),
+                tag_no_case("localtimestamp"),
+                tag_no_case("localtime"),
+            )),
+            |n: LocatedSpan<&[u8]>| {
+                let s = String::from_utf8(n.to_vec()).expect("Only constant string literals");
+                match dialect {
+                    Dialect::MySQL => s.into(),
+                    Dialect::PostgreSQL => s.to_lowercase().into(),
+                }
+            },
+        )(i)?;
+
+        Ok((
+            i,
+            FunctionExpr::Call {
+                name,
+                arguments: vec![],
+            },
+        ))
+    }
 }
 
 fn timestamp_field() -> impl Fn(LocatedSpan<&[u8]>) -> NomSqlResult<&[u8], TimestampField> {
@@ -400,7 +406,7 @@ pub fn function_expr(
             upper(dialect),
             substring(dialect),
             function_call(dialect),
-            function_call_without_parens,
+            function_call_without_parens(dialect),
         ))(i)
     }
 }

nom-sql/src/insert.rs

@@ -324,7 +324,7 @@ mod tests {
                         Expr::Literal("test".into()),
                         Expr::Literal("test".into()),
                         Expr::Call(FunctionExpr::Call {
-                            name: "CURRENT_TIMESTAMP".into(),
+                            name: "current_timestamp".into(),
                             arguments: vec![],
                         }),
                     ],],

nom-sql/src/select.rs

@@ -1887,7 +1887,7 @@ mod tests {
                             Expr::Literal(Literal::String("foo".to_owned()),)
                         ),
                         FieldDefinitionExpr::from(Expr::Call(FunctionExpr::Call {
-                            name: "CURRENT_TIME".into(),
+                            name: "current_time".into(),
                             arguments: vec![]
                         })),
                     ],

readyset-sql-parsing/tests/parity.rs

@@ -325,3 +325,10 @@ fn test_convert_with_using() {
 fn test_empty_insert() {
     check_parse_mysql!("INSERT INTO t () VALUES ()");
 }
+
+#[test]
+fn test_column_default_without_parens() {
+    check_parse_both!(
+        "CREATE TABLE IF NOT EXISTS m (version VARCHAR(50) PRIMARY KEY NOT NULL, run_on TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP);"
+    );
+}