templates: add map functions

Similar to switch and .StyleSwitch, add map and .StyleMap to work on
lists. An extra "exclude" item is available to filter elements out of
the list.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Tested-by: Inwit <inwit@sindominio.net>

6 files changed, 75 insertions, 0 deletions

diff --git a/commands/commands_test.go b/commands/commands_test.go
index e510ebe1..7c3ec84f 100644
--- a/commands/commands_test.go
+++ b/commands/commands_test.go
@@ -106,3 +106,5 @@ func (d *dummyData) PendingKeys() string                       { return "" }
 func (d *dummyData) Role() string                              { return "inbox" }
 func (d *dummyData) Style(string, string) string               { return "" }
 func (d *dummyData) StyleSwitch(string, ...models.Case) string { return "" }
+
+func (d *dummyData) StyleMap([]string, ...models.Case) []string { return []string{} }
diff --git a/config/templates.go b/config/templates.go
index 40e7e450..97ba89b8 100644
--- a/config/templates.go
+++ b/config/templates.go
@@ -108,3 +108,5 @@ func (d *dummyData) Role() string                    { return "inbox" }
 
 func (d *dummyData) Style(string, string) string               { return "" }
 func (d *dummyData) StyleSwitch(string, ...models.Case) string { return "" }
+
+func (d *dummyData) StyleMap([]string, ...models.Case) []string { return []string{} }
diff --git a/doc/aerc-templates.7.scd b/doc/aerc-templates.7.scd
index 6919e5dd..394e22b6 100644
--- a/doc/aerc-templates.7.scd
+++ b/doc/aerc-templates.7.scd
@@ -402,6 +402,16 @@ aerc provides the following additional functions:
 	{{.StyleSwitch (.From | names | join ", ") (case `Tim` "cyan") (case `Robin` "pink-blink") (default "blue")}}
 	```
 
+*.StyleMap*
+	Apply user-defined styles (see *aerc-stylesets*(7)) to elements of
+	a string list. The logic is the same than *.StyleSwitch* but works on
+	a list of elements. An additional *exclude* option is available to
+	remove the matching elements from the list.
+
+	```
+	{{.StyleMap .Labels (exclude .Folder) (exclude `^spam$`) (case `^inbox$` "red") (case `^Archive/.*` "green") (default "blue") | join " "}}
+	```
+
 *version*
 	Returns the version of aerc, which can be useful for things like X-Mailer.
 
@@ -426,6 +436,15 @@ aerc provides the following additional functions:
 	{{switch .Folder (case `^INBOX$` "📥") (case `^Archive/.*` "🗃") (default "📁")}}
 	```
 
+*map*
+	Transform a string list into another one. The logic is the same than
+	*switch* but works on a list of elements. An additional *exclude* option
+	is available to remove the matching elements from the list.
+
+	```
+	{{map .Labels (exclude .Folder) (exclude `^spam$`) (case `^inbox$` "📥") (case `^Archive/.*` "🗃") | join " "}}
+	```
+
 *Function chaining*
 	All of the template functions can be chained together if needed.
 
diff --git a/lib/state/templates.go b/lib/state/templates.go
index 8c7df3e8..36f7b725 100644
--- a/lib/state/templates.go
+++ b/lib/state/templates.go
@@ -560,3 +560,23 @@ func (d *templateData) StyleSwitch(content string, cases ...models.Case) string
 	}
 	return content
 }
+
+func (d *templateData) StyleMap(elems []string, cases ...models.Case) []string {
+	mapped := make([]string, 0, len(elems))
+top:
+	for _, e := range elems {
+		for _, c := range cases {
+			if c.Matches(e) {
+				if c.Skip() {
+					continue top
+				}
+				cfg := config.Ui.ForAccount(d.Account())
+				style := cfg.GetUserStyle(c.Value())
+				e = parse.ApplyStyle(style, e)
+				break
+			}
+		}
+		mapped = append(mapped, e)
+	}
+	return mapped
+}
diff --git a/lib/templates/functions.go b/lib/templates/functions.go
index b331dc85..9380bc7b 100644
--- a/lib/templates/functions.go
+++ b/lib/templates/functions.go
@@ -255,12 +255,18 @@ func compactDir(path string) string {
 type (
 	Case    struct{ expr, value string }
 	Default struct{ value string }
+	Exclude struct{ expr string }
 )
 
 func (c *Case) Matches(s string) bool    { return parse.MatchCache(s, c.expr) }
 func (c *Case) Value() string            { return c.value }
+func (c *Case) Skip() bool               { return false }
 func (d *Default) Matches(s string) bool { return true }
 func (d *Default) Value() string         { return d.value }
+func (d *Default) Skip() bool            { return false }
+func (e *Exclude) Matches(s string) bool { return parse.MatchCache(s, e.expr) }
+func (e *Exclude) Value() string         { return "" }
+func (e *Exclude) Skip() bool            { return true }
 
 func switch_(value string, cases ...models.Case) string {
 	for _, c := range cases {
@@ -279,6 +285,28 @@ func default_(value string) models.Case {
 	return &Default{value: value}
 }
 
+func exclude(expr string) models.Case {
+	return &Exclude{expr: expr}
+}
+
+func map_(elements []string, cases ...models.Case) []string {
+	mapped := make([]string, 0, len(elements))
+top:
+	for _, e := range elements {
+		for _, c := range cases {
+			if c.Matches(e) {
+				if c.Skip() {
+					continue top
+				}
+				e = c.Value()
+				break
+			}
+		}
+		mapped = append(mapped, e)
+	}
+	return mapped
+}
+
 var templateFuncs = template.FuncMap{
 	"quote":         quote,
 	"wrapText":      wrapText,
@@ -304,4 +332,6 @@ var templateFuncs = template.FuncMap{
 	"switch":        switch_,
 	"case":          case_,
 	"default":       default_,
+	"map":           map_,
+	"exclude":       exclude,
 }
diff --git a/models/templates.go b/models/templates.go
index ae57c3fb..eb696ccc 100644
--- a/models/templates.go
+++ b/models/templates.go
@@ -51,9 +51,11 @@ type TemplateData interface {
 	PendingKeys() string
 	Style(string, string) string
 	StyleSwitch(string, ...Case) string
+	StyleMap([]string, ...Case) []string
 }
 
 type Case interface {
 	Matches(string) bool
 	Value() string
+	Skip() bool
 }