feat: add lexer

common.go

@@ -0,0 +1,27 @@
+// Copyright (c) HashiCorp, Inc.
+
+package mql
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// isNil reports if a is nil
+func isNil(a any) bool {
+	if a == nil {
+		return true
+	}
+	switch reflect.TypeOf(a).Kind() {
+	case reflect.Ptr, reflect.Map, reflect.Chan, reflect.Slice, reflect.Func:
+		return reflect.ValueOf(a).IsNil()
+	}
+	return false
+}
+
+// panicIfNil will panic if a is nil
+func panicIfNil(a any, caller, missing string) {
+	if isNil(a) {
+		panic(fmt.Sprintf("%s: missing %s", caller, missing))
+	}
+}

common_test.go

@@ -0,0 +1,63 @@
+package mql
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_panicIfNil(t *testing.T) {
+
+	assert.Panics(t, func() {
+		panicIfNil(nil, "test", "missing bit")
+	})
+}
+
+func Test_isNil(t *testing.T) {
+	t.Parallel()
+
+	var testErrNilPtr *testError
+	var testMapNilPtr map[string]struct{}
+	var testArrayNilPtr *[1]string
+	var testChanNilPtr *chan string
+	var testSliceNilPtr *[]string
+	var testFuncNil func()
+
+	var testChanString chan string
+
+	tc := []struct {
+		i    any
+		want bool
+	}{
+		{i: &testError{}, want: false},
+		{i: testError{}, want: false},
+		{i: &map[string]struct{}{}, want: false},
+		{i: map[string]struct{}{}, want: false},
+		{i: [1]string{}, want: false},
+		{i: &[1]string{}, want: false},
+		{i: &testChanString, want: false},
+		{i: "string", want: false},
+		{i: []string{}, want: false},
+		{i: func() {}, want: false},
+		{i: nil, want: true},
+		{i: testErrNilPtr, want: true},
+		{i: testMapNilPtr, want: true},
+		{i: testArrayNilPtr, want: true},
+		{i: testChanNilPtr, want: true},
+		{i: testChanString, want: true},
+		{i: testSliceNilPtr, want: true},
+		{i: testFuncNil, want: true},
+	}
+
+	for i, tc := range tc {
+		t.Run(fmt.Sprintf("test #%d", i+1), func(t *testing.T) {
+			assert := assert.New(t)
+			assert.Equal(tc.want, isNil(tc.i))
+		})
+	}
+}
+
+type testError struct{}
+
+func (*testError) Error() string { return "error" }

error.go

@@ -0,0 +1,7 @@
+package mql
+
+import "errors"
+
+var (
+	ErrInvalidNotEqual        = errors.New(`invalid "!=" token`)
+)

go.mod

@@ -1,3 +1,11 @@
 module mql
 
 go 1.20
+
+require github.com/stretchr/testify v1.8.4
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=