add trim, ltrim, rtrim functions

cmd/genji/doc/doc_test.go

@@ -28,8 +28,10 @@ func TestFunctions(t *testing.T) {
 				t.Run(fmt.Sprintf("%s.%s is documented and has all its arguments mentioned", pkgname, fname), func(t *testing.T) {
 					str, err := doc.DocString(fmt.Sprintf("%s.%s", pkgname, fname))
 					assert.NoError(t, err)
-					for i := 0; i < def.Arity(); i++ {
-						require.Contains(t, trimDocPromt(str), fmt.Sprintf("arg%d", i+1))
+					if def.Arity() > 0 {
+						for i := 0; i < def.Arity(); i++ {
+							require.Contains(t, trimDocPromt(str), fmt.Sprintf("arg%d", i+1))
+						}
 					}
 				})
 			}

cmd/genji/doc/functions.go

@@ -33,4 +33,7 @@ var mathDocs = functionDocs{
 var stringsDocs = functionDocs{
 	"lower":  "The lower function returns arg1 to lower-case if arg1 evals to string",
 	"upper":  "The upper function returns arg1 to upper-case if arg1 evals to string",
+	"trim":   "The trim function returns arg1 with leading and trailing characters removed. space by default or arg2",
+	"ltrim":   "The ltrim function returns arg1 with leading characters removed. space by default or arg2",
+	"rtrim":   "The rtrim function returns arg1 with trailing characters removed. space by default or arg2",
 }

internal/expr/functions/definition.go

@@ -23,8 +23,8 @@ type Packages map[string]Definitions
 
 func DefaultPackages() Packages {
 	return Packages{
-		"":     BuiltinDefinitions(),
-		"math": MathFunctions(),
+		"":        BuiltinDefinitions(),
+		"math":    MathFunctions(),
 		"strings": StringsDefinitions(),
 	}
 }
@@ -57,13 +57,20 @@ func (fd *definition) Name() string {
 }
 
 func (fd *definition) Function(args ...expr.Expr) (expr.Function, error) {
+	if fd.arity == -1 {
+		return fd.constructorFn(args...)
+	}
+
 	if len(args) != fd.arity {
 		return nil, fmt.Errorf("%s() takes %d argument(s), not %d", fd.name, fd.arity, len(args))
 	}
 	return fd.constructorFn(args...)
 }
 
 func (fd *definition) String() string {
+	if fd.arity < 0 {
+		fd.arity = 0
+	}
 	args := make([]string, 0, fd.arity)
 	for i := 0; i < fd.arity; i++ {
 		args = append(args, fmt.Sprintf("arg%d", i+1))

internal/expr/functions/strings.go

@@ -24,6 +24,27 @@ var stringsFunctions = Definitions{
 			return &Upper{Expr: args[0]}, nil
 		},
 	},
+	"trim": &definition{
+		name:  "trim",
+		arity: -1,
+		constructorFn: func(args ...expr.Expr) (expr.Function, error) {
+			return &Trim{Expr: args, TrimFunc: strings.Trim, Name: "TRIM"}, nil
+		},
+	},
+	"ltrim": &definition{
+		name:  "ltrim",
+		arity: -1,
+		constructorFn: func(args ...expr.Expr) (expr.Function, error) {
+			return &Trim{Expr: args, TrimFunc: strings.TrimLeft, Name: "LTRIM"}, nil
+		},
+	},
+	"rtrim": &definition{
+		name:  "rtrim",
+		arity: -1,
+		constructorFn: func(args ...expr.Expr) (expr.Function, error) {
+			return &Trim{Expr: args, TrimFunc: strings.TrimRight, Name: "RTRIM"}, nil
+		},
+	},
 }
 
 func StringsDefinitions() Definitions {
@@ -109,3 +130,72 @@ func (s *Upper) Params() []expr.Expr { return []expr.Expr{s.Expr} }
 func (s *Upper) String() string {
 	return fmt.Sprintf("UPPER(%v)", s.Expr)
 }
+
+// TRIM removes leading and trailing characters from a string based on the given input.
+// LTRIM removes leading characters
+// RTRIM removes trailing characters
+// By default remove space " "
+type Trim struct {
+	Expr []expr.Expr
+	TrimFunc TrimFunc
+	Name string
+}
+
+type TrimFunc func(string, string) string
+
+func (s *Trim) Eval(env *environment.Environment) (types.Value, error) {
+	if len(s.Expr) > 2 {
+		return nil, fmt.Errorf("misuse of string function %v()", s.Name)
+	}
+
+	input, err := s.Expr[0].Eval(env)
+	if err != nil {
+		return nil, err
+	}
+
+	if input.Type() != types.TextValue {
+		return types.NewNullValue(), nil
+	}
+
+	var cutset = " "
+
+	if len(s.Expr) == 2 {
+		remove, err := s.Expr[1].Eval(env)
+		if err != nil {
+			return nil, err
+		}
+		if remove.Type() != types.TextValue {
+			return types.NewNullValue(), nil
+		}
+		cutset = types.As[string](remove)
+	}
+
+	trimmed := s.TrimFunc(types.As[string](input), cutset)
+
+	return types.NewTextValue(trimmed), nil
+}
+
+func (s *Trim) IsEqual(other []expr.Expr) bool {
+	if other == nil || len(s.Expr) != len(other){
+		return false
+	}
+
+	for i := range s.Expr {
+		if !expr.Equal(s.Expr[i], other[i]) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func (s *Trim) Params() []expr.Expr { 
+	return s.Expr
+}
+
+func (s *Trim) String() string {
+	if (len(s.Expr) == 1){
+		return fmt.Sprintf("%v(%v)", s.Name, s.Expr[0])
+	}
+	return fmt.Sprintf("%v(%v, %v)", s.Name, s.Expr[0], s.Expr[1])
+}

sqltests/SELECT/STRINGS/ltrim.sql

@@ -0,0 +1,112 @@
+-- setup:
+CREATE TABLE test(
+    a TEXT
+);
+
+INSERT INTO test (a) VALUES (" hello "), ("!hello!"),  ("     !hello!  ");
+
+-- test: LTRIM TEXT default
+SELECT strings.LTRIM(a) FROM test;
+/* result:
+{
+    "LTRIM(a)": "hello "
+}
+{
+    "LTRIM(a)": "!hello!"
+}
+{
+    "LTRIM(a)": "!hello!  "
+}
+*/
+
+
+-- test: LTRIM TEXT with param
+SELECT strings.LTRIM(a, "!") FROM test;
+/* result:
+{
+    "LTRIM(a, \"!\")": " hello "
+}
+{
+    "LTRIM(a, \"!\")": "hello!"
+}
+{
+    "LTRIM(a, \"!\")": "     !hello!  "
+}
+*/
+
+-- test: LTRIM TEXT with multiple char params
+SELECT strings.LTRIM(a, " !") FROM test;
+/* result:
+{
+    "LTRIM(a, \" !\")": "hello "
+}
+{
+    "LTRIM(a, \" !\")": "hello!"
+}
+{
+    "LTRIM(a, \" !\")": "hello!  "
+}
+*/
+
+
+-- test: LTRIM TEXT with multiple char params
+SELECT strings.LTRIM(a, "hel !") FROM test;
+/* result:
+{
+    "LTRIM(a, \"hel !\")": "o "
+}
+{
+    "LTRIM(a, \"hel !\")": "o!"
+}
+{
+    "LTRIM(a, \"hel !\")": "o!  "
+}
+*/
+
+
+-- test: LTRIM BOOL
+SELECT strings.LTRIM(true);
+/* result:
+{
+    "LTRIM(true)": NULL
+}
+*/
+
+-- test: LTRIM INT
+SELECT strings.LTRIM(42);
+/* result:
+{
+    "LTRIM(42)": NULL
+}
+*/
+
+-- test: LTRIM DOUBLE
+SELECT strings.LTRIM(42.42);
+/* result:
+{
+    "LTRIM(42.42)": NULL
+}
+*/
+
+-- test: LTRIM ARRAY
+SELECT strings.LTRIM([1, 2]);
+/* result:
+{
+    "LTRIM([1, 2])": NULL
+}
+*/
+-- test: LTRIM DOCUMENT
+SELECT strings.LTRIM({a: 1});
+/* result:
+{
+    "LTRIM({a: 1})": NULL
+}
+*/
+
+-- test: LTRIM STRING wrong param
+SELECT strings.LTRIM(" hello ", 42);
+/* result:
+{
+    "LTRIM(\" hello \", 42)": NULL
+}
+*/

sqltests/SELECT/STRINGS/rtrim.sql

@@ -0,0 +1,112 @@
+-- setup:
+CREATE TABLE test(
+    a TEXT
+);
+
+INSERT INTO test (a) VALUES (" hello "), ("!hello!"),  ("     !hello!  ");
+
+-- test: RTRIM TEXT default
+SELECT strings.RTRIM(a) FROM test;
+/* result:
+{
+    "RTRIM(a)": " hello"
+}
+{
+    "RTRIM(a)": "!hello!"
+}
+{
+    "RTRIM(a)": "     !hello!"
+}
+*/
+
+
+-- test: RTRIM TEXT with param
+SELECT strings.RTRIM(a, "!") FROM test;
+/* result:
+{
+    "RTRIM(a, \"!\")": " hello "
+}
+{
+    "RTRIM(a, \"!\")": "!hello"
+}
+{
+    "RTRIM(a, \"!\")": "     !hello!  "
+}
+*/
+
+-- test: RTRIM TEXT with multiple char params
+SELECT strings.RTRIM(a, " !") FROM test;
+/* result:
+{
+    "RTRIM(a, \" !\")": " hello"
+}
+{
+    "RTRIM(a, \" !\")": "!hello"
+}
+{
+    "RTRIM(a, \" !\")": "     !hello"
+}
+*/
+
+
+-- test: RTRIM TEXT with multiple char params
+SELECT strings.RTRIM(a, "hel !") FROM test;
+/* result:
+{
+    "RTRIM(a, \"hel !\")": " hello"
+}
+{
+    "RTRIM(a, \"hel !\")": "!hello"
+}
+{
+    "RTRIM(a, \"hel !\")": "     !hello"
+}
+*/
+
+
+-- test: RTRIM BOOL
+SELECT strings.RTRIM(true);
+/* result:
+{
+    "RTRIM(true)": NULL
+}
+*/
+
+-- test: RTRIM INT
+SELECT strings.RTRIM(42);
+/* result:
+{
+    "RTRIM(42)": NULL
+}
+*/
+
+-- test: RTRIM DOUBLE
+SELECT strings.RTRIM(42.42);
+/* result:
+{
+    "RTRIM(42.42)": NULL
+}
+*/
+
+-- test: RTRIM ARRAY
+SELECT strings.RTRIM([1, 2]);
+/* result:
+{
+    "RTRIM([1, 2])": NULL
+}
+*/
+-- test: RTRIM DOCUMENT
+SELECT strings.RTRIM({a: 1});
+/* result:
+{
+    "RTRIM({a: 1})": NULL
+}
+*/
+
+-- test: RTRIM STRING wrong param
+SELECT strings.RTRIM(" hello ", 42);
+/* result:
+{
+    "RTRIM(\" hello \", 42)": NULL
+}
+*/