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-rw-r--r--replacer.go45
-rw-r--r--replacer_test.go6
2 files changed, 38 insertions, 13 deletions
diff --git a/replacer.go b/replacer.go
index a38cf55..cabe089 100644
--- a/replacer.go
+++ b/replacer.go
@@ -27,10 +27,11 @@ import (
type Replacer interface {
Set(variable, value string)
Delete(variable string)
- Map(ReplacementFunc)
+ Map(ReplacerFunc)
ReplaceAll(input, empty string) string
ReplaceKnown(input, empty string) string
ReplaceOrErr(input string, errOnEmpty, errOnUnknown bool) (string, error)
+ ReplaceFunc(input string, f ReplacementFunc) (string, error)
}
// NewReplacer returns a new Replacer.
@@ -38,7 +39,7 @@ func NewReplacer() Replacer {
rep := &replacer{
static: make(map[string]string),
}
- rep.providers = []ReplacementFunc{
+ rep.providers = []ReplacerFunc{
globalDefaultReplacements,
rep.fromStatic,
}
@@ -46,13 +47,13 @@ func NewReplacer() Replacer {
}
type replacer struct {
- providers []ReplacementFunc
+ providers []ReplacerFunc
static map[string]string
}
// Map adds mapFunc to the list of value providers.
// mapFunc will be executed only at replace-time.
-func (r *replacer) Map(mapFunc ReplacementFunc) {
+func (r *replacer) Map(mapFunc ReplacerFunc) {
r.providers = append(r.providers, mapFunc)
}
@@ -77,14 +78,14 @@ func (r *replacer) fromStatic(key string) (val string, ok bool) {
// that are empty or not recognized will cause an error to
// be returned.
func (r *replacer) ReplaceOrErr(input string, errOnEmpty, errOnUnknown bool) (string, error) {
- return r.replace(input, "", false, errOnEmpty, errOnUnknown)
+ return r.replace(input, "", false, errOnEmpty, errOnUnknown, nil)
}
// ReplaceKnown is like ReplaceAll but only replaces
// placeholders that are known (recognized). Unrecognized
// placeholders will remain in the output.
func (r *replacer) ReplaceKnown(input, empty string) string {
- out, _ := r.replace(input, empty, false, false, false)
+ out, _ := r.replace(input, empty, false, false, false, nil)
return out
}
@@ -93,12 +94,21 @@ func (r *replacer) ReplaceKnown(input, empty string) string {
// whether they are recognized or not. Values that are empty
// string will be substituted with empty.
func (r *replacer) ReplaceAll(input, empty string) string {
- out, _ := r.replace(input, empty, true, false, false)
+ out, _ := r.replace(input, empty, true, false, false, nil)
return out
}
+// ReplaceFunc calls ReplaceAll efficiently replaces placeholders in input with
+// their values. All placeholders are replaced in the output
+// whether they are recognized or not. Values that are empty
+// string will be substituted with empty.
+func (r *replacer) ReplaceFunc(input string, f ReplacementFunc) (string, error) {
+ return r.replace(input, "", true, false, false, f)
+}
+
func (r *replacer) replace(input, empty string,
- treatUnknownAsEmpty, errOnEmpty, errOnUnknown bool) (string, error) {
+ treatUnknownAsEmpty, errOnEmpty, errOnUnknown bool,
+ f ReplacementFunc) (string, error) {
if !strings.Contains(input, string(phOpen)) {
return input, nil
}
@@ -134,6 +144,13 @@ func (r *replacer) replace(input, empty string,
for _, mapFunc := range r.providers {
if val, ok := mapFunc(key); ok {
found = true
+ if f != nil {
+ var err error
+ val, err = f(key, val)
+ if err != nil {
+ return "", err
+ }
+ }
if val == "" {
if errOnEmpty {
return "", fmt.Errorf("evaluated placeholder %s%s%s is empty",
@@ -174,12 +191,12 @@ func (r *replacer) replace(input, empty string,
return sb.String(), nil
}
-// ReplacementFunc is a function that returns a replacement
+// ReplacerFunc is a function that returns a replacement
// for the given key along with true if the function is able
// to service that key (even if the value is blank). If the
// function does not recognize the key, false should be
// returned.
-type ReplacementFunc func(key string) (val string, ok bool)
+type ReplacerFunc func(key string) (val string, ok bool)
func globalDefaultReplacements(key string) (string, bool) {
// check environment variable
@@ -206,6 +223,14 @@ func globalDefaultReplacements(key string) (string, bool) {
return "", false
}
+// ReplacementFunc is a function that is called when a
+// replacement is being performed. It receives the
+// variable (i.e. placeholder name) and the value that
+// will be the replacement, and returns the value that
+// will actually be the replacement, or an error. Note
+// that errors are sometimes ignored by replacers.
+type ReplacementFunc func(variable, val string) (string, error)
+
// nowFunc is a variable so tests can change it
// in order to obtain a deterministic time.
var nowFunc = time.Now
diff --git a/replacer_test.go b/replacer_test.go
index fa9b569..88e83f5 100644
--- a/replacer_test.go
+++ b/replacer_test.go
@@ -133,7 +133,7 @@ func TestReplacerSet(t *testing.T) {
func TestReplacerReplaceKnown(t *testing.T) {
rep := replacer{
- providers: []ReplacementFunc{
+ providers: []ReplacerFunc{
// split our possible vars to two functions (to test if both functions are called)
func(key string) (val string, ok bool) {
switch key {
@@ -239,7 +239,7 @@ func TestReplacerDelete(t *testing.T) {
func TestReplacerMap(t *testing.T) {
rep := testReplacer()
- for i, tc := range []ReplacementFunc{
+ for i, tc := range []ReplacerFunc{
func(key string) (val string, ok bool) {
return "", false
},
@@ -317,7 +317,7 @@ func TestReplacerNew(t *testing.T) {
func testReplacer() replacer {
return replacer{
- providers: make([]ReplacementFunc, 0),
+ providers: make([]ReplacerFunc, 0),
static: make(map[string]string),
}
}