Add <T>Set ([]*<T>) type generator

codegen.sh

@@ -15,6 +15,7 @@ function gofmt {
 echo "=== go generate ==="
 cd system/db && go generate && cd ../..
 cd crm/db && go generate && cd ../..
+cd crm/types && go generate && cd ../..
 cd crm/repository && go generate && cd ../..
 cd sam/db && go generate && cd ../..
 

codegen/v2/type-set.go

@@ -0,0 +1,119 @@
+package main
+
+// Makeshift *Set type generator for functions like Walk(), Filter(), FindByID() & IDs()
+
+import (
+	"bytes"
+	"fmt"
+	"go/format"
+	"os"
+	"text/template"
+
+	"github.com/pkg/errors"
+)
+
+const tmplTypeSet = `package types
+
+type (
+{{ range .Sets }}
+	// {{ . }}Set slice of {{ . }}
+	{{ . }}Set []*{{ . }}
+{{- end }}
+)
+
+{{ range .Sets }}
+// Walk iterates through every slice item and calls w({{ . }}) err
+func (set {{ . }}Set) Walk(w func(*{{ . }}) error) (err error) {
+	for i := range set {
+		if err = w(set[i]); err != nil {
+			return
+		}
+	}
+
+	return
+}
+
+// Filter iterates through every slice item, calls f({{ . }}) (bool, err) and return filtered slice
+func (set {{ . }}Set) Filter(f func(*{{ . }}) (bool, error)) (out {{ . }}Set, err error) {
+	var ok bool
+	out = {{ . }}Set{}
+	for i := range set {
+		if ok, err = f(set[i]); err != nil {
+			return
+		} else if ok {
+			out = append(out, set[i])
+		}
+	}
+
+	return
+}
+
+// Finds slice item by its ID property
+func (set {{ . }}Set) FindByID(ID uint64) *{{ . }} {
+	for i := range set {
+		if set[i].ID == ID {
+			return set[i]
+		}
+	}
+
+	return nil
+}
+
+// Returns a slice of uint64s from all items in the set
+func (set {{ . }}Set) IDs() (IDs []uint64) {
+	IDs = make([]uint64, len(set))
+
+	for i := range set {
+		IDs[i] = set[i].ID
+	}
+
+	return
+}
+{{- end }}
+`
+
+func main() {
+	t := template.New("")
+
+	tpl := template.Must(template.Must(t.Clone()).Parse(tmplTypeSet))
+
+	if len(os.Args) < 3 {
+		exit(errors.New("type-set.go <output-file> <type type2 type3 ...>"))
+	}
+
+	l := len(os.Args) - 1
+	outputFile := os.Args[l]
+	payload := struct{ Sets []string }{Sets: os.Args[1:l]}
+
+	buf := bytes.Buffer{}
+
+	if err := tpl.Execute(&buf, payload); err != nil {
+		exit(err)
+	} else {
+		fmtsrc, err := format.Source(buf.Bytes())
+		if err != nil {
+			stderr("fmt warn: %v", err)
+			fmtsrc = buf.Bytes()
+		}
+
+		output, err := os.Create(outputFile)
+		if err != nil {
+			exit(err)
+		}
+
+		defer output.Close()
+
+		if _, err := output.Write(fmtsrc); err != nil {
+			exit(err)
+		}
+	}
+}
+
+func stderr(format string, a ...interface{}) {
+	_, _ = os.Stderr.WriteString(fmt.Sprintf(format, a...))
+}
+
+func exit(err error) {
+	stderr("error: %v", err)
+	os.Exit(1)
+}