Implement sqlFinalSemicolon option

Refs #50

Author: nene

src/options.ts

@@ -5,6 +5,7 @@ export interface SqlPluginOptions {
   sqlKeywordCase: "preserve" | "upper" | "lower";
   sqlParamTypes: NonNullable<CstParserOptions["paramTypes"]>;
   sqlCanonicalSyntax: boolean;
+  sqlFinalSemicolon: boolean;
   sqlAcceptUnsupportedGrammar: boolean;
 }
 
@@ -52,6 +53,13 @@ export const options: SupportOptions = {
       "Enforces one true style of SQL syntax (adds and removes keywords)",
     // Since 0.11.0
   },
+  sqlFinalSemicolon: {
+    type: "boolean",
+    category: "SQL",
+    default: true,
+    description: "Enforces a semicolon at the end of last SQL statement",
+    // Since 0.13.0
+  },
   sqlAcceptUnsupportedGrammar: {
     type: "boolean",
     category: "SQL",

src/syntax/program.ts

@@ -7,7 +7,9 @@ import { AllPrettierOptions } from "src/options";
 export const programMap: CstToDocMap<Program> = {
   program: (print, node, path, options) =>
     print("statements").map((doc, i) =>
-      printStatement(doc, i, node.statements, options),
+      i === node.statements.length - 1
+        ? printFinalStatement(doc, i, node.statements, options)
+        : printStatement(doc, i, node.statements, options),
     ),
 };
 
@@ -31,3 +33,23 @@ const printStatement = (
     return [";", hardline, doc];
   }
 };
+
+const printFinalStatement = (
+  doc: Doc,
+  i: number,
+  statements: Node[],
+  options: AllPrettierOptions<Program>,
+): Doc => {
+  const stmtDoc = printStatement(doc, i, statements, options);
+  if (statements[i].type === "empty") {
+    // When the final statement is an empty statement,
+    // this means we have inserted a semicolon and newline before it.
+    // So nothing else is needed.
+    return stmtDoc;
+  } else {
+    // If the last statement is not empty,
+    // this means sqlFinalSemicolon option is false,
+    // so we need to add an empty line after it.
+    return [stmtDoc, hardline];
+  }
+};

src/transform/transformCst.ts

@@ -17,8 +17,10 @@ export const transformCst: TransformFn = (
     // so we don't need to worry about comments interfering with other transforms
     moveCommentsToRoot,
     stripTrailingCommas,
-    addFinalSemicolon,
   ];
+  if (options.sqlFinalSemicolon) {
+    transforms.push(addFinalSemicolon);
+  }
   if (options.sqlCanonicalSyntax) {
     transforms.push(processAliasAs, canonicOperators, canonicKeywords);
   }

test/options/finalSemicolon.test.ts

@@ -0,0 +1,57 @@
+import dedent from "dedent-js";
+import { rawPretty } from "../test_utils";
+
+// In these tests we use rawPretty()
+// to also test that formatted file always ends with final newline.
+describe("sqlFinalSemicolon option", () => {
+  describe("with sqlFinalSemicolon enabled (the default)", () => {
+    it(`adds semicolon to statement without a semicolon`, async () => {
+      expect(await rawPretty(`SELECT 1`)).toBe(dedent`
+        SELECT 1;
+
+      `);
+    });
+
+    it(`ensures semicolon after last statement`, async () => {
+      expect(await rawPretty(`SELECT 1; SELECT 2; SELECT 3`)).toBe(dedent`
+        SELECT 1;
+        SELECT 2;
+        SELECT 3;
+
+      `);
+    });
+  });
+
+  describe("with sqlFinalSemicolon disabled", () => {
+    it(`does not add semicolon to statement without a semicolon`, async () => {
+      expect(await rawPretty(`SELECT 1`, { sqlFinalSemicolon: false })).toBe(
+        dedent`
+          SELECT 1
+
+        `,
+      );
+    });
+
+    it(`adds no semicolon after last statement`, async () => {
+      expect(
+        await rawPretty(`SELECT 1; SELECT 2; SELECT 3`, {
+          sqlFinalSemicolon: false,
+        }),
+      ).toBe(dedent`
+        SELECT 1;
+        SELECT 2;
+        SELECT 3
+
+      `);
+    });
+
+    it(`does not remove an existing trailing semicolon`, async () => {
+      expect(await rawPretty(`SELECT 1;`, { sqlFinalSemicolon: false })).toBe(
+        dedent`
+          SELECT 1;
+
+        `,
+      );
+    });
+  });
+});

test/statement.test.ts

@@ -4,13 +4,6 @@ import { rawPretty, rawTest } from "./test_utils";
 // In these tests we use rawPretty()
 // to also test that formatted file always ends with final newline.
 describe("statement", () => {
-  it(`adds semicolon to statement without a semicolon`, async () => {
-    expect(await rawPretty(`SELECT 1`)).toBe(dedent`
-      SELECT 1;
-
-    `);
-  });
-
   it(`formats statement ending with semicolon`, async () => {
     expect(await rawPretty(`SELECT 1;`)).toBe(dedent`
       SELECT 1;
@@ -27,15 +20,6 @@ describe("statement", () => {
     `);
   });
 
-  it(`ensures semicolon after last statement`, async () => {
-    expect(await rawPretty(`SELECT 1; SELECT 2; SELECT 3`)).toBe(dedent`
-      SELECT 1;
-      SELECT 2;
-      SELECT 3;
-
-    `);
-  });
-
   it(`preserves empty line between statements`, async () => {
     rawTest(dedent`
       SELECT 1;