Fix wrongly parse +1 as a number in expression: 1+1 (#91)

Author: git-hulk

parser/ast.go

@@ -3766,13 +3766,10 @@ func (w *WhenClause) End() Pos {
 func (w *WhenClause) String(level int) string {
 	var builder strings.Builder
 	builder.WriteString("WHEN ")
-	builder.WriteString(NewLine(level + 1))
 	builder.WriteString(w.When.String(level))
-	builder.WriteString(NewLine(level + 1))
 	builder.WriteString(" THEN ")
 	builder.WriteString(w.Then.String(level))
 	if w.Else != nil {
-		builder.WriteString(NewLine(level + 1))
 		builder.WriteString(" ELSE ")
 		builder.WriteString(w.Else.String(level))
 	}
@@ -3799,7 +3796,7 @@ func (w *WhenClause) Accept(visitor ASTVisitor) error {
 type CaseExpr struct {
 	CasePos Pos
 	EndPos  Pos
-	Expr    Expr
+	Expr    Expr // optional
 	Whens   []*WhenClause
 	ElsePos Pos
 	Else    Expr
@@ -3816,27 +3813,27 @@ func (c *CaseExpr) End() Pos {
 func (c *CaseExpr) String(level int) string {
 	var builder strings.Builder
 	builder.WriteString("CASE ")
-	builder.WriteString(NewLine(level))
-	builder.WriteString(c.Expr.String(level))
+	if c.Expr != nil {
+		builder.WriteString(c.Expr.String(level))
+	}
 	for _, when := range c.Whens {
-		builder.WriteString(NewLine(level))
 		builder.WriteString(when.String(level))
 	}
 	if c.Else != nil {
-		builder.WriteString("ELSE ")
-		builder.WriteString(NewLine(level))
+		builder.WriteString(" ELSE ")
 		builder.WriteString(c.Else.String(level))
 	}
-	builder.WriteString(NewLine(level))
-	builder.WriteString("END")
+	builder.WriteString(" END")
 	return builder.String()
 }
 
 func (c *CaseExpr) Accept(visitor ASTVisitor) error {
 	visitor.enter(c)
 	defer visitor.leave(c)
-	if err := c.Expr.Accept(visitor); err != nil {
-		return err
+	if c.Expr != nil {
+		if err := c.Expr.Accept(visitor); err != nil {
+			return err
+		}
 	}
 	for _, when := range c.Whens {
 		if err := when.Accept(visitor); err != nil {

parser/lexer.go

@@ -256,8 +256,17 @@ func (l *Lexer) peekToken() (*Token, error) {
 	return token, nil
 }
 
+func (l *Lexer) hasPrecedenceToken(last *Token) bool {
+	return last != nil && (last.Kind == TokenIdent ||
+		last.Kind == TokenKeyword ||
+		last.Kind == TokenInt ||
+		last.Kind == TokenFloat ||
+		last.Kind == TokenString)
+}
+
 func (l *Lexer) consumeToken() error {
 	// clear last token
+	lastToken := l.lastToken
 	l.lastToken = nil
 	l.skipComments()
 	l.skipSpace()
@@ -281,7 +290,8 @@ func (l *Lexer) consumeToken() error {
 		}
 
 	case '+', '-':
-		if l.peekOk(1) && IsDigit(l.peekN(1)) {
+		// hasPrecedenceToken is used to distinguish between unary and binary operators
+		if !l.hasPrecedenceToken(lastToken) && l.peekOk(1) && IsDigit(l.peekN(1)) {
 			return l.consumeNumber()
 		} else if l.peekOk(1) && l.peekN(1) == '>' {
 			l.lastToken = &Token{

parser/parser_column.go

@@ -591,11 +591,14 @@ func (p *Parser) parseColumnCaseExpr(pos Pos) (*CaseExpr, error) {
 		return nil, err
 	}
 
-	expr, err := p.parseExpr(p.Pos())
-	if err != nil {
-		return nil, err
+	// case expr is optional
+	if !p.matchKeyword(KeywordWhen) {
+		expr, err := p.parseExpr(p.Pos())
+		if err != nil {
+			return nil, err
+		}
+		caseExpr.Expr = expr
 	}
-	caseExpr.Expr = expr
 
 	// WHEN expr THEN expr
 	whenClauses := make([]*WhenClause, 0)

parser/testdata/query/format/select_expr.sql

@@ -0,0 +1,7 @@
+-- Origin SQL:
+SELECT 1+1
+
+-- Format SQL:
+
+SELECT 
+  1 + 1;

parser/testdata/query/format/select_when_condition.sql

@@ -0,0 +1,7 @@
+-- Origin SQL:
+select case when false then 'hello' else 'world' end;
+
+-- Format SQL:
+
+SELECT 
+  CASE WHEN false THEN 'hello' ELSE 'world' END;

parser/testdata/query/output/select_expr.sql.golden.json

@@ -0,0 +1,48 @@
+[
+  {
+    "SelectPos": 0,
+    "StatementEnd": 10,
+    "With": null,
+    "Top": null,
+    "SelectColumns": {
+      "ListPos": 7,
+      "ListEnd": 10,
+      "HasDistinct": false,
+      "Items": [
+        {
+          "LeftExpr": {
+            "NumPos": 7,
+            "NumEnd": 8,
+            "Literal": "1",
+            "Base": 10
+          },
+          "Operation": "+",
+          "RightExpr": {
+            "NumPos": 9,
+            "NumEnd": 10,
+            "Literal": "1",
+            "Base": 10
+          },
+          "HasGlobal": false,
+          "HasNot": false
+        }
+      ]
+    },
+    "From": null,
+    "ArrayJoin": null,
+    "Window": null,
+    "Prewhere": null,
+    "Where": null,
+    "GroupBy": null,
+    "WithTotal": false,
+    "Having": null,
+    "OrderBy": null,
+    "LimitBy": null,
+    "Limit": null,
+    "Settings": null,
+    "Format": null,
+    "UnionAll": null,
+    "UnionDistinct": null,
+    "Except": null
+  }
+]

parser/testdata/query/output/select_when_condition.sql.golden.json

@@ -0,0 +1,61 @@
+[
+  {
+    "SelectPos": 0,
+    "StatementEnd": 0,
+    "With": null,
+    "Top": null,
+    "SelectColumns": {
+      "ListPos": 7,
+      "ListEnd": 0,
+      "HasDistinct": false,
+      "Items": [
+        {
+          "CasePos": 7,
+          "EndPos": 0,
+          "Expr": null,
+          "Whens": [
+            {
+              "WhenPos": 12,
+              "ThenPos": 23,
+              "When": {
+                "Name": "false",
+                "QuoteType": 1,
+                "NamePos": 17,
+                "NameEnd": 22
+              },
+              "Then": {
+                "LiteralPos": 29,
+                "LiteralEnd": 34,
+                "Literal": "hello"
+              },
+              "ElsePos": 0,
+              "Else": null
+            }
+          ],
+          "ElsePos": 36,
+          "Else": {
+            "LiteralPos": 42,
+            "LiteralEnd": 47,
+            "Literal": "world"
+          }
+        }
+      ]
+    },
+    "From": null,
+    "ArrayJoin": null,
+    "Window": null,
+    "Prewhere": null,
+    "Where": null,
+    "GroupBy": null,
+    "WithTotal": false,
+    "Having": null,
+    "OrderBy": null,
+    "LimitBy": null,
+    "Limit": null,
+    "Settings": null,
+    "Format": null,
+    "UnionAll": null,
+    "UnionDistinct": null,
+    "Except": null
+  }
+]

parser/testdata/query/select_expr.sql

@@ -0,0 +1 @@
+SELECT 1+1

parser/testdata/query/select_when_condition.sql

@@ -0,0 +1 @@
+select case when false then 'hello' else 'world' end;