diff options
| -rw-r--r-- | replacer.go | 45 | ||||
| -rw-r--r-- | replacer_test.go | 6 |
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), } } |