lang: funcs: strings: Count substr in string

lang/funcs/core/strings/count_func.go

@@ -0,0 +1,49 @@
+// Mgmt
+// Copyright (C) 2013-2021+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package corestrings
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
+	"github.com/purpleidea/mgmt/lang/types"
+)
+
+func init() {
+	simple.ModuleRegister(ModuleName, "count", &types.FuncValue{
+		T: types.NewType("func(s str, substr str) str"),
+		V: Count,
+	})
+}
+
+// Count counts the number of non-overlapping instances of substr in s. If
+// substr is an empty string, Count returns 0 if empty string and len(string) if
+// substr is empty
+func Count(input []types.Value) (types.Value, error) {
+	s, substr := input[0].Str(), input[1].Str()
+	if s == "" {
+		return &types.StrValue{V: "0"}, nil
+	}
+
+	count := strings.Count(s, substr)
+	if substr == "" {
+		count--
+	}
+	return &types.StrValue{V: fmt.Sprint(count)}, nil
+}

lang/funcs/core/strings/count_func_test.go

@@ -0,0 +1,69 @@
+// Mgmt
+// Copyright (C) 2013-2021+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package corestrings
+
+import (
+	"testing"
+
+	"github.com/purpleidea/mgmt/lang/types"
+)
+
+func TestCount(t *testing.T) {
+	countTests := []struct {
+		name     string
+		s        string
+		substr   string
+		expected string
+		err      error
+	}{
+		// Success
+		{"with many results", "A copy is just an identical image. There is the possibility that a single virus could destroy an entire set of systems and copies do not give rise to variety and originality. Life perpetuates itself through diversity and this includes the ability to sacrifice itself when necessary. Cells repeat the process of degeneration and regeneration until one day they die, obliterating an entire set of memory and information. Only genes remain. Why continually repeat this cycle? Simply to survive by avoiding the weaknesses of an unchanging system.", "to", "3", nil},
+		{"with 1 result", "hello world, hi world, howdy world", "hello", "1", nil},
+		{"with no matches", "hello world, whats good?", "yo", "0", nil},
+		{"counts substrings", "once upon a time", "on", "2", nil},
+		{"with blank substring, returns len(str)", "123456789", "", "9", nil},
+		{"with blank string, returns 0", "", "", "0", nil},
+	}
+
+	for _, test := range countTests {
+		t.Run(test.name, func(t *testing.T) {
+			output, err := Count([]types.Value{
+				&types.StrValue{V: test.s},
+				&types.StrValue{V: test.substr},
+			})
+			expectedStr := &types.StrValue{V: test.expected}
+
+			if test.err != nil && err.Error() != test.err.Error() {
+				t.Errorf("s: %s, substr %s, expected error: %q, got %q", test.s, test.substr, test.err, err)
+				return
+			} else if test.err != nil && err == nil {
+				t.Errorf("s: %s, substr: %s, expected error: %v, but got nil", test.s, test.substr, test.err)
+				return
+			} else if test.err == nil && err != nil {
+				t.Errorf("s: %s, substr %s, did not expect error but got: %#v", test.s, test.substr, err)
+				return
+			}
+			if err1 := output.Cmp(expectedStr); err1 != nil {
+				t.Errorf("s: %s, substr: %s, expected: %s, got: %s", test.s, test.substr, expectedStr, output)
+				return
+			}
+
+		})
+	}
+
+}