Add option for specifying case for identifiers

docs/identifierCase.md

@@ -0,0 +1,58 @@
+# identifierCase
+
+Converts identifiers to upper or lowercase.
+
+Note: An identifier is a name of a SQL object.
+There are two types of SQL identifiers: ordinary identifiers and quoted identifiers.
+Only ordinary identifiers are subject to be converted.
+
+## Options
+
+- `"preserve"` (default) preserves the original case.
+- `"upper"` converts to uppercase.
+- `"lower"` converts to lowercase.
+
+### preserve
+
+```
+select
+  count(a.Column1),
+  max(a.Column2 + a.Column3),
+  a.Column4 AS myCol
+from
+  Table1 as a
+where
+  Column6
+  and Column7
+group by Column4
+```
+
+### upper
+
+```
+select
+  count(A.COLUMN1),
+  max(A.COLUMN2 + A.COLUMN3),
+  A.COLUMN4 AS MYCOL
+from
+  TABLE1 as A
+where
+  COLUMN6
+  and COLUMN7
+group by COLUMN4
+```
+
+### lower
+
+```
+select
+  count(a.column1),
+  max(a.column2 + a.column3),
+  a.column4 AS mycol
+from
+  table1 as a
+where
+  column6
+  and column7
+group by column4
+```

src/FormatOptions.ts

@@ -6,6 +6,8 @@ export type IndentStyle = 'standard' | 'tabularLeft' | 'tabularRight';
 
 export type KeywordCase = 'preserve' | 'upper' | 'lower';
 
+export type IdentifierCase = 'preserve' | 'upper' | 'lower';
+
 export type CommaPosition = 'before' | 'after' | 'tabular';
 
 export type LogicalOperatorNewline = 'before' | 'after';
@@ -14,6 +16,7 @@ export interface FormatOptions {
   tabWidth: number;
   useTabs: boolean;
   keywordCase: KeywordCase;
+  identifierCase: IdentifierCase;
   indentStyle: IndentStyle;
   logicalOperatorNewline: LogicalOperatorNewline;
   tabulateAlias: boolean;

src/formatter/ExpressionFormatter.ts

@@ -145,7 +145,9 @@ export default class ExpressionFormatter {
   private formatArraySubscript(node: ArraySubscriptNode) {
     this.withComments(node.array, () => {
       this.layout.add(
-        node.array.type === NodeType.keyword ? this.showKw(node.array) : node.array.text
+        node.array.type === NodeType.keyword
+          ? this.showKw(node.array)
+          : this.showIdentifier(node.array)
       );
     });
     this.formatNode(node.parenthesis);
@@ -286,7 +288,7 @@ export default class ExpressionFormatter {
   }
 
   private formatIdentifier(node: IdentifierNode) {
-    this.layout.add(node.text, WS.SPACE);
+    this.layout.add(this.showIdentifier(node), WS.SPACE);
   }
 
   private formatParameter(node: ParameterNode) {
@@ -506,4 +508,19 @@ export default class ExpressionFormatter {
         return node.text.toLowerCase();
     }
   }
+
+  private showIdentifier(node: IdentifierNode): string {
+    if (node.tokenType === TokenType.IDENTIFIER || node.tokenType === TokenType.ARRAY_IDENTIFIER) {
+      switch (this.cfg.identifierCase) {
+        case 'preserve':
+          return node.text;
+        case 'upper':
+          return node.text.toUpperCase();
+        case 'lower':
+          return node.text.toLowerCase();
+      }
+    } else {
+      return node.text;
+    }
+  }
 }

src/index.ts

@@ -16,6 +16,7 @@ export type {
 export type {
   IndentStyle,
   KeywordCase,
+  IdentifierCase,
   CommaPosition,
   LogicalOperatorNewline,
   FormatOptions,

src/parser/ast.ts

@@ -125,6 +125,7 @@ export interface PropertyAccessNode extends BaseNode {
 
 export interface IdentifierNode extends BaseNode {
   type: NodeType.identifier;
+  tokenType: TokenType;
   text: string;
 }
 

src/parser/grammar.ne

@@ -1,7 +1,7 @@
 @preprocessor typescript
 @{%
 import LexerAdapter from './LexerAdapter.js';
-import { NodeType, AstNode, CommentNode, KeywordNode } from './ast.js';
+import { NodeType, AstNode, CommentNode, KeywordNode, IdentifierNode } from './ast.js';
 import { Token, TokenType } from '../lexer/token.js';
 
 // The lexer here is only to provide the has() method,
@@ -16,6 +16,12 @@ const lexer = new LexerAdapter(chunk => []);
 // which otherwise produce single element nested inside two arrays
 const unwrap = <T>([[el]]: T[][]): T => el;
 
+const toIdentifierNode = (token: Token): IdentifierNode => ({
+  type: NodeType.identifier,
+  tokenType: token.type,
+  text: token.text,
+});
+
 const toKeywordNode = (token: Token): KeywordNode => ({
   type: NodeType.keyword,
   tokenType: token.type,
@@ -202,7 +208,7 @@ atomic_expression ->
 array_subscript -> %ARRAY_IDENTIFIER _ square_brackets {%
   ([arrayToken, _, brackets]) => ({
     type: NodeType.array_subscript,
-    array: addComments({ type: NodeType.identifier, text: arrayToken.text}, { trailing: _ }),
+    array: addComments({ type: NodeType.identifier, tokenType: TokenType.ARRAY_IDENTIFIER, text: arrayToken.text}, { trailing: _ }),
     parenthesis: brackets,
   })
 %}
@@ -309,7 +315,7 @@ operator -> ( %OPERATOR ) {% ([[token]]) => ({ type: NodeType.operator, text: to
 identifier ->
   ( %IDENTIFIER
   | %QUOTED_IDENTIFIER
-  | %VARIABLE ) {% ([[token]]) => ({ type: NodeType.identifier, text: token.text }) %}
+  | %VARIABLE ) {% ([[token]]) => toIdentifierNode(token) %}
 
 parameter ->
   ( %NAMED_PARAMETER

src/sqlFormatter.ts

@@ -41,6 +41,7 @@ const defaultOptions: FormatOptions = {
   tabWidth: 2,
   useTabs: false,
   keywordCase: 'preserve',
+  identifierCase: 'preserve',
   indentStyle: 'standard',
   logicalOperatorNewline: 'before',
   tabulateAlias: false,

test/behavesLikeSqlFormatter.ts

@@ -9,6 +9,7 @@ import supportsTabWidth from './options/tabWidth.js';
 import supportsUseTabs from './options/useTabs.js';
 import supportsExpressionWidth from './options/expressionWidth.js';
 import supportsKeywordCase from './options/keywordCase.js';
+import supportsIdentifierCase from './options/identifierCase.js';
 import supportsIndentStyle from './options/indentStyle.js';
 import supportsCommaPosition from './options/commaPosition.js';
 import supportsLinesBetweenQueries from './options/linesBetweenQueries.js';
@@ -30,6 +31,7 @@ export default function behavesLikeSqlFormatter(format: FormatFn) {
   supportsTabWidth(format);
   supportsUseTabs(format);
   supportsKeywordCase(format);
+  supportsIdentifierCase(format);
   supportsIndentStyle(format);
   supportsLinesBetweenQueries(format);
   supportsExpressionWidth(format);

test/features/arrayAndMapAccessors.ts

@@ -23,6 +23,18 @@ export default function supportsArrayAndMapAccessors(format: FormatFn) {
     `);
   });
 
+  it('supports square brackets for map lookup - uppercase', () => {
+    const result = format(`SELECT Alpha['a'], Beta['gamma'].zeTa, yotA['foo.bar-baz'];`, {
+      identifierCase: 'upper',
+    });
+    expect(result).toBe(dedent`
+      SELECT
+        ALPHA['a'],
+        BETA['gamma'].ZETA,
+        YOTA['foo.bar-baz'];
+    `);
+  });
+
   it('supports namespaced array identifiers', () => {
     const result = format(`SELECT foo.coalesce['blah'];`);
     expect(result).toBe(dedent`
@@ -46,4 +58,36 @@ export default function supportsArrayAndMapAccessors(format: FormatFn) {
         foo./* comment */ arr[1];
     `);
   });
+
+  it('supports namespaced array identifiers in uppercase', () => {
+    const result = format(`SELECT Foo.Coalesce['Blah'];`, { identifierCase: 'upper' });
+    expect(result).toBe(dedent`
+      SELECT
+        FOO.COALESCE['Blah'];
+    `);
+  });
+
+  it('supports namespaced array identifiers in lowercase', () => {
+    const result = format(`SELECT Foo.Coalesce['Blah'];`, { identifierCase: 'lower' });
+    expect(result).toBe(dedent`
+      SELECT
+        foo.coalesce['Blah'];
+    `);
+  });
+
+  it('formats namespaced array accessor with comment in-between in uppercase', () => {
+    const result = format(`SELECT foo./* comment */arr[1];`, { identifierCase: 'upper' });
+    expect(result).toBe(dedent`
+      SELECT
+        FOO./* comment */ ARR[1];
+    `);
+  });
+
+  it('formats namespaced array accessor with comment in-between in lowercase', () => {
+    const result = format(`SELECT Foo./* comment */Arr[1];`, { identifierCase: 'lower' });
+    expect(result).toBe(dedent`
+      SELECT
+        foo./* comment */ arr[1];
+    `);
+  });
 }

test/options/identifierCase.ts

@@ -0,0 +1,81 @@
+import dedent from 'dedent-js';
+
+import { FormatFn } from '../../src/sqlFormatter.js';
+
+export default function supportsIdentifierCase(format: FormatFn) {
+  it('preserves identifier case by default', () => {
+    const result = format(
+      dedent`
+        select Abc, 'mytext' as MyText from tBl1 left join Tbl2 where colA > 1 and colB = 3`
+    );
+    expect(result).toBe(dedent`
+      select
+        Abc,
+        'mytext' as MyText
+      from
+        tBl1
+        left join Tbl2
+      where
+        colA > 1
+        and colB = 3
+    `);
+  });
+
+  it('converts identifiers to uppercase', () => {
+    const result = format(
+      dedent`
+        select Abc, 'mytext' as MyText from tBl1 left join Tbl2 where colA > 1 and colB = 3`,
+      { identifierCase: 'upper' }
+    );
+    expect(result).toBe(dedent`
+      select
+        ABC,
+        'mytext' as MYTEXT
+      from
+        TBL1
+        left join TBL2
+      where
+        COLA > 1
+        and COLB = 3
+    `);
+  });
+
+  it('converts identifiers to lowercase', () => {
+    const result = format(
+      dedent`
+        select Abc, 'mytext' as MyText from tBl1 left join Tbl2 where colA > 1 and colB = 3`,
+      { identifierCase: 'lower' }
+    );
+    expect(result).toBe(dedent`
+      select
+        abc,
+        'mytext' as mytext
+      from
+        tbl1
+        left join tbl2
+      where
+        cola > 1
+        and colb = 3
+    `);
+  });
+
+  it('does not uppercase quoted identifiers', () => {
+    const result = format(`select "abc" as foo`, {
+      identifierCase: 'upper',
+    });
+    expect(result).toBe(dedent`
+      select
+        "abc" as FOO
+    `);
+  });
+
+  it('converts multi-part identifiers to uppercase', () => {
+    const result = format('select Abc from Part1.Part2.Part3', { identifierCase: 'upper' });
+    expect(result).toBe(dedent`
+      select
+        ABC
+      from
+        PART1.PART2.PART3
+    `);
+  });
+}