feat: multi-line formatting for permission expressions

pkg/dsl/parser/parser.go

@@ -33,6 +33,8 @@ type Parser struct {
 	l *lexer.Lexer
 	// the current token being processed
 	currentToken token.Token
+	// the token before currentToken
+	previousToken token.Token
 	// the next token after currentToken
 	peekToken token.Token
 	// a slice of error messages that are generated during parsing
@@ -82,6 +84,8 @@ func (p *Parser) next() {
 		peek := p.l.NextToken()
 		// if the token is not an ignored token (e.g. whitespace or comments), update the currentToken and peekToken fields and exit the loop
 		if !token.IsIgnores(peek.Type) {
+			// set the previousToken before changing currentToken
+			p.previousToken = p.currentToken
 			// set the currentToken field to the previous peekToken value
 			p.currentToken = p.peekToken
 			// set the peekToken field to the new peek value
@@ -118,6 +122,18 @@ func (p *Parser) currentTokenIs(tokens ...token.Type) bool {
 	return false
 }
 
+// previousTokenIs checks if the Parser's previousToken type is any of the given types
+func (p *Parser) previousTokenIs(tokens ...token.Type) bool {
+	for _, t := range tokens {
+		if p.previousToken.Type == t {
+			// if a match is found, return true
+			return true
+		}
+	}
+	// if no match is found, return false
+	return false
+}
+
 // peekTokenIs checks if the Parser's peekToken is any of the given token types
 func (p *Parser) peekTokenIs(tokens ...token.Type) bool {
 	// iterate through the given token types and check if any of them match the peekToken's type
@@ -588,6 +604,11 @@ func (p *Parser) parseExpression(precedence int) (ast.Expression, error) {
 	var exp ast.Expression
 	var err error
 
+	if p.currentTokenIs(token.NEWLINE) && p.previousTokenIs(token.LP, token.AND, token.OR, token.NOT, token.ASSIGN) {
+		// advance to the next token
+		p.next()
+	}
+
 	if p.currentTokenIs(token.LP) {
 		p.next() // Consume the left parenthesis.
 		exp, err = p.parseExpression(LOWEST)

pkg/dsl/parser/parser_test.go

@@ -849,5 +849,157 @@ var _ = Describe("parser", func() {
 			Expect(es.Expression.(*ast.InfixExpression).Right.(*ast.InfixExpression).Left.(*ast.Identifier).String()).Should(Equal("parent.admin"))
 			Expect(es.Expression.(*ast.InfixExpression).Right.(*ast.InfixExpression).Right.(*ast.Identifier).String()).Should(Equal("parent.member"))
 		})
+
+		It("Case 24 - Multi-line Permission Expression w/ Rule", func() {
+			pr := NewParser(`
+			entity account {
+    			relation owner @user
+    			attribute balance float
+
+    			permission withdraw = check_balance(request.amount, balance) and 
+					owner
+			}
+
+			rule check_balance(amount float, balance float) {
+				balance >= amount && amount <= 5000
+			}
+			`)
+
+			schema, err := pr.Parse()
+			Expect(err).ShouldNot(HaveOccurred())
+
+			st := schema.Statements[0].(*ast.EntityStatement)
+
+			Expect(st.Name.Literal).Should(Equal("account"))
+
+			r1 := st.RelationStatements[0].(*ast.RelationStatement)
+			Expect(r1.Name.Literal).Should(Equal("owner"))
+
+			for _, a := range r1.RelationTypes {
+				Expect(a.Type.Literal).Should(Equal("user"))
+			}
+
+			a1 := st.AttributeStatements[0].(*ast.AttributeStatement)
+			Expect(a1.Name.Literal).Should(Equal("balance"))
+			Expect(a1.AttributeType.Type.Literal).Should(Equal("float"))
+
+			p1 := st.PermissionStatements[0].(*ast.PermissionStatement)
+			Expect(p1.Name.Literal).Should(Equal("withdraw"))
+
+			es1 := p1.ExpressionStatement.(*ast.ExpressionStatement)
+
+			Expect(es1.Expression.(*ast.InfixExpression).Left.(*ast.Call).String()).Should(Equal("check_balance(request.amount, balance)"))
+			Expect(es1.Expression.(*ast.InfixExpression).Right.(*ast.Identifier).String()).Should(Equal("owner"))
+
+			rs1 := schema.Statements[1].(*ast.RuleStatement)
+
+			Expect(rs1.Name.Literal).Should(Equal("check_balance"))
+			Expect(rs1.Expression).Should(Equal("\nbalance >= amount && amount <= 5000\n\t\t"))
+		})
+
+		It("Case 25 - Multi-line Permission Expression w/ Rule", func() {
+			pr := NewParser(`
+			entity account {
+    			relation owner @user
+    			attribute balance float
+
+    			permission withdraw = 
+					check_balance(request.amount, balance) and owner
+			}
+
+			rule check_balance(amount float, balance float) {
+				balance >= amount && amount <= 5000
+			}
+			`)
+
+			schema, err := pr.Parse()
+			Expect(err).ShouldNot(HaveOccurred())
+
+			st := schema.Statements[0].(*ast.EntityStatement)
+
+			Expect(st.Name.Literal).Should(Equal("account"))
+
+			r1 := st.RelationStatements[0].(*ast.RelationStatement)
+			Expect(r1.Name.Literal).Should(Equal("owner"))
+
+			for _, a := range r1.RelationTypes {
+				Expect(a.Type.Literal).Should(Equal("user"))
+			}
+
+			a1 := st.AttributeStatements[0].(*ast.AttributeStatement)
+			Expect(a1.Name.Literal).Should(Equal("balance"))
+			Expect(a1.AttributeType.Type.Literal).Should(Equal("float"))
+
+			p1 := st.PermissionStatements[0].(*ast.PermissionStatement)
+			Expect(p1.Name.Literal).Should(Equal("withdraw"))
+
+			es1 := p1.ExpressionStatement.(*ast.ExpressionStatement)
+
+			Expect(es1.Expression.(*ast.InfixExpression).Left.(*ast.Call).String()).Should(Equal("check_balance(request.amount, balance)"))
+			Expect(es1.Expression.(*ast.InfixExpression).Right.(*ast.Identifier).String()).Should(Equal("owner"))
+
+			rs1 := schema.Statements[1].(*ast.RuleStatement)
+
+			Expect(rs1.Name.Literal).Should(Equal("check_balance"))
+			Expect(rs1.Expression).Should(Equal("\nbalance >= amount && amount <= 5000\n\t\t"))
+		})
+
+		It("Case 26 - Multi-line Permission Expression w/ Rule - should fail", func() {
+			pr := NewParser(`
+			entity account {
+    			relation owner @user
+    			attribute balance float
+
+    			permission withdraw = check_balance(request.amount, balance)
+					owner
+			}
+
+			rule check_balance(amount float, balance float) {
+				balance >= amount && amount <= 5000
+			}
+			`)
+
+			_, err := pr.Parse()
+			Expect(err).Should(HaveOccurred())
+		})
+
+		It("Case 26 - Multi-line Permission Complex Expression w/ Rule", func() {
+			pr := NewParser(`
+entity report {
+    relation parent @organization
+    relation team @team
+    attribute confidentiality_level double
+
+    permission view = 
+		confidentiality_level_high(confidentiality_level) and 
+		parent.director or 
+		confidentiality_level_medium_high(confidentiality_level) and 
+		(parent.director or team.lead) or 
+		confidentiality_level_medium(confidentiality_level) and (team.lead or team.member) or 
+		confidentiality_level_low(confidentiality_level) and 
+		parent.member
+    permission edit = team.lead
+}
+
+rule confidentiality_level_high(confidentiality_level double) {
+    confidentiality_level == 4.0
+}
+
+rule confidentiality_level_medium_high(confidentiality_level double) {
+    confidentiality_level == 3.0
+}
+
+rule confidentiality_level_medium(confidentiality_level double) {
+    confidentiality_level == 2.0
+}
+
+rule confidentiality_level_low(confidentiality_level double) {
+    confidentiality_level == 1.0
+}
+			`)
+
+			_, err := pr.Parse()
+			Expect(err).ShouldNot(HaveOccurred())
+		})
 	})
 })