Replace Dynamic with template.FuncMap

Must better and more resilient. Also allows the creation of template
domain languages by individual Cmd authors.

First `indent` builtin created.

README.md

@@ -371,6 +371,13 @@ want the specific reasons.
   When and if dependencies on them become an issue it can be addressed
   then.
 
+* **Not exporting Dynamic FuncMap builtins**
+
+  Since those builtins will land in `mark` subpackage eventually, don't
+  want to build any dependencies on them now that will break. The
+  builtins themselves can obviously be used immediately and has a much
+  smaller chance of changing in the future.
+
 ## Style Guidelines
 
 * Everything through `go fmt` or equiv, no exceptions

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/rwxrob/scan v0.6.1
 	github.com/rwxrob/structs v0.5.1
 	github.com/rwxrob/term v0.2.6
-	github.com/rwxrob/to v0.4.5
+	github.com/rwxrob/to v0.4.6
 )
 
 require (

go.sum

@@ -10,6 +10,8 @@ github.com/rwxrob/term v0.2.6 h1:C8BqqHaEh8MGYp1cVrPRlDAYPEK3HfvhGjf7l5AvnV8=
 github.com/rwxrob/term v0.2.6/go.mod h1:II0qQ7aHUdPniZCAPWOdYwugcZqdmRmEWIJQN7Z8NA0=
 github.com/rwxrob/to v0.4.5 h1:ILFn40Zd8Tbz0+vmMcA9WyBkAZzeIltr39STLeoxP/o=
 github.com/rwxrob/to v0.4.5/go.mod h1:lojk6scni4ZRYjnKJO/f2DVRTW0BB6l9LZQ/NvZZt4Y=
+github.com/rwxrob/to v0.4.6 h1:VXYmc2wI3aGq3HzecgMWYLiFZRVy1PlZIVOGRt0S8V0=
+github.com/rwxrob/to v0.4.6/go.mod h1:lojk6scni4ZRYjnKJO/f2DVRTW0BB6l9LZQ/NvZZt4Y=
 golang.org/x/crypto v0.0.0-20220331220935-ae2d96664a29/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/crypto v0.0.0-20220408190544-5352b0902921 h1:iU7T1X1J6yxDr0rda54sWGkHgOp5XJrqm79gcNlC2VM=
 golang.org/x/crypto v0.0.0-20220408190544-5352b0902921/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=

z/cmd.go

@@ -18,6 +18,7 @@ import (
 	"github.com/rwxrob/fn/maps"
 	"github.com/rwxrob/fn/redu"
 	"github.com/rwxrob/structs/qstack"
+	"github.com/rwxrob/to"
 )
 
 type Cmd struct {
@@ -47,7 +48,8 @@ type Cmd struct {
 	MaxParm  int    `json:"-"` // maximum number of params required
 	ReqConf  bool   `json:"-"` // requires Z.Conf be assigned
 	ReqCache bool   `json:"-"` // requires Z.Cache be assigned
-	Dynamic  DynMap `json:"-"` // dynamic attributes
+
+	Dynamic template.FuncMap `json:"-"` // dynamic attributes
 
 	_aliases  map[string]*Cmd   // see cacheAliases called from Run->Seek->Resolve
 	_sections map[string]string // see cacheSections called from Run
@@ -61,26 +63,6 @@ type Section struct {
 	Body  string
 }
 
-// DynMap is a key value map of Dyn functions.
-type DynMap map[string]DynFunc
-
-// DynFunc is a dynamic attribute that evaluated and returned at runtime.
-// Access them from Cmd.Dyn[<name>]. They are slower to access so don't
-// abuse them.
-type DynFunc func(x *Cmd) string
-
-// Dyn returns the output of the DynFunc value for the give key from the
-// Cmd.Dynamic DynMap if not nil. Returns empty string otherwise.
-func (x *Cmd) Dyn(key string) string {
-	if x.Dynamic == nil {
-		return ""
-	}
-	if v, has := x.Dynamic[key]; has {
-		return v(x)
-	}
-	return ""
-}
-
 func (s Section) GetTitle() string { return s.Title }
 func (s Section) GetBody() string  { return s.Body }
 
@@ -472,7 +454,8 @@ func (x *Cmd) Q(q string) string {
 // as the data object source for the template. It is called by the Get*
 // family of field accessors but can be called directly as well.
 func (x *Cmd) Fill(tmpl string) string {
-	t, err := template.New("t").Parse(tmpl)
+	funcs := to.MergedMaps(markFuncMap, x.Dynamic)
+	t, err := template.New("t").Funcs(funcs).Parse(tmpl)
 	if err != nil {
 		log.Println(err)
 	}

z/markfunc.go

@@ -0,0 +1,19 @@
+package Z
+
+import (
+	"text/template"
+
+	"github.com/rwxrob/to"
+)
+
+// This file contains the BonzaiMark builtins that Cmd authors can use
+// in their Description and other places where templated BonzaiMark is
+// allowed.
+
+var markFuncMap = template.FuncMap{
+	"indent": indent,
+}
+
+func indent(n int, in string) string {
+	return to.Indented(in, IndentBy+n)
+}