Change handling of spaces and empty list values (#10)

Change handling of spaces and empty list values:

- add `keep-spaces` and `keep-empty` options to struct tags to restore prior behavior
- add `string.TrimSpaces()` before parsing argument value if `keep-spaces` is not specified
- add `string.TrimSpaces()` on individual list values if `keep-spaces` is not specified
- drop empty list values if `keep-empty` is not specified
- Update `README.md` to describe new behavior
- Update `RELEASES.md`  with new spaces behavior for upcoming v0.5.0
- Update go.mod packages to latest

README.md

@@ -133,8 +133,17 @@ The `opts` tag can consist of:
 - `default:` : a default value for the field if not specified on the
   command-line
 - `env:` : the name of an environment variable that can override the default
-- `sep:`: a separator for fields that can accept multiple values. By default,
-  multiple values must be specified by repeating the option flag multiple times.
+- `sep:`: a list separator characters for fields that can accept multiple
+  values. To use a comma or colon as separator, those characters must be escaped
+  with a double-backslash (`\\,` or `\\:`). To use spaces and newlines as
+  separator, the special value `\\s` can be used. Unless a separator is
+  specified with this option, additional values must be specified by repeating
+  the option flag multiple times.
+- `keep-spaces` : when specified with no value, this option preserves the spaces
+  around the argument values, that would otherwise be trimmed by default.
+- `keep-empty` : for fields thar accept multiple values using a separator, this
+  option preserve empty values after splitting and trimming, that would
+  otherwise be dropped by default.
 - `name:`: the display name for the value, used when printing out description of
   the field.
 
@@ -160,10 +169,24 @@ standard interface, and includes:
 
 Unless otherwise initialized, all pointer fields are initialized to `nil`, all
 slice fields are initialized to an empty slice, and all scalar fields are
-initialized to their built-in zero value. If the built-in zero value is a valid
-value and if the command needs to determine if an option has been provided, a
+initialized to their built-in zero value. If the command needs to differentiate
+between the built-in zero value of a scalar field and a specified zero value, a
 pointer type should be used and checked against `nil`.
 
+By default, slice field values must be provided by repeating the option flag
+multiple times, once of each value. If a separator is defined (`sep:`), multiple
+or all values can be provided with one command-line argument. To provide multiple values through an environment variable, a separated must be defined.
+
+> New in v0.5.0: A breaking change has been introduced to better handle lists of
+> values and spaces around values. Prior behavior can be restores with the
+> `keep-spaces` option for all fields and `keep-empty` for lists. With this new
+> behavior, spaces around the values are automatically trimmed, and empty values
+> after trimming are dropped from value lists. In effect, this allows for
+> trailing separators to be ignored, and for list values to be specified with
+> additional spaces around the separators, including newlines.  Note that, even
+> with `keep-empty`, if the last character is a separator, the last empty values
+> is always drop, as was the case in prior versions.
+
 In a command-line interface, all option flags are optional. Required options
 should use positional arguments. Positional arguments are required unless
 defined with a pointer type, and only if all subsequent positional arguments are

RELEASES.md

@@ -1,4 +1,4 @@
-# v0.5.0
+# v0.5.0-rc
 
 ## Key Features
 
@@ -11,6 +11,12 @@
       custom completion handler
     - `DefaultFilenameCompletion()` matching default shell completion
     - `MatchingFilenameCompletion()` for pattern based filename matching
+- Surrounding spaces are automatically trimmed from values unless `keep-spaces`
+  option is specified on the argument
+- List values automatically drop empty values unless `keep-empty` option is
+  specified on the argument. Note that even with `keep-empty`, if the last
+  character is a separator, the last empty values is always drop, as was the
+  case in the prior versions.
 
 ## Code changes
 

go.mod

@@ -4,14 +4,13 @@ go 1.17
 
 require (
 	github.com/maargenton/go-errors v1.0.0
-	github.com/maargenton/go-fileutils v0.6.2
+	github.com/maargenton/go-fileutils v0.6.4
 	github.com/maargenton/go-testpredicate v1.3.0
-	golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b
-	golang.org/x/tools v0.1.10
+	golang.org/x/term v0.10.0
+	golang.org/x/tools v0.11.0
 )
 
 require (
-	golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 // indirect
-	golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	golang.org/x/mod v0.12.0 // indirect
+	golang.org/x/sys v0.10.0 // indirect
 )

go.sum

@@ -2,51 +2,70 @@ github.com/maargenton/fileutil v0.4.1/go.mod h1:+GxNHyNo3uqVv2QJPfmdzIByRSLf5qKK
 github.com/maargenton/go-errors v0.0.0-20200720205202-f0b27f4dc001/go.mod h1:qw42L2So9gQZM8ZrnBoBc4deYTaL89dyE+2wuNGELMg=
 github.com/maargenton/go-errors v1.0.0 h1:gNDwTfN3VHwLog2w/BfeGlCTjwjJ6H0NeMKS+4xCNE4=
 github.com/maargenton/go-errors v1.0.0/go.mod h1:yVvhNp6mywh/FFoTYbi2WPH7oP0U9AZXtvGa8SDIxOQ=
-github.com/maargenton/go-fileutils v0.6.2 h1:D2MdHYUTFr+KQdq3aQfkUqpcgkDOUQNZ3bGY7URuBAU=
-github.com/maargenton/go-fileutils v0.6.2/go.mod h1:9gClkdrb1nDcnC2w1vCvClhJESGjK9wQJ2RusLAxOSk=
+github.com/maargenton/go-fileutils v0.6.4 h1:4rtH1Bwcv3C+ps72kjlAAQeJ36fYg8WSHPCIyfZqqjU=
+github.com/maargenton/go-fileutils v0.6.4/go.mod h1:9gClkdrb1nDcnC2w1vCvClhJESGjK9wQJ2RusLAxOSk=
 github.com/maargenton/go-testpredicate v0.4.4/go.mod h1:sn267JpJ65uvLQ7VtYzPLvXQiw0tHHw+KbCFzxRPOww=
 github.com/maargenton/go-testpredicate v0.6.4/go.mod h1:lUPR99Ipl1o49oRb5wEUwb/7KXrwc1FAVR6aZmCmoS8=
 github.com/maargenton/go-testpredicate v1.3.0 h1:uy9g71epeAmI2CXHnEYKFDwueXppvLHZMoUfAF82K9o=
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-github.com/yuin/goldmark v1.4.1/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
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 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/crypto v0.11.0/go.mod h1:xgJhtzW8F9jGdVFWZESrid1U1bjeNy4zgy5cRr/CIio=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
-golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 h1:kQgndtyPBW/JIYERgdxfwMYh3AVStj88WQTlNDi2a+o=
-golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3/go.mod h1:3p9vT2HGsQu2K1YbXdKPJLVgG5VJdoTa1poYQBtP1AY=
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 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
-golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
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 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
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+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
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 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
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+golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
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 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b h1:9zKuko04nR4gjZ4+DNjHqRlAJqbJETHwiNKDqTfOjfE=
-golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
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 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
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 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
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pkg/option/option.go

@@ -32,6 +32,8 @@ type T struct {
 	Default     string
 	Env         string
 	Sep         string // optional separator
+	KeepSpaces  bool
+	KeepEmpty   bool
 	Description string
 	ValueName   string // optional name for the value
 	Position    int    // set to non-zero for fields capturing positional arguments
@@ -161,13 +163,19 @@ func (opt *T) SetBool() {
 func (opt *T) SetValue(s string) error {
 	var fv = opt.opts.target.FieldByIndex(opt.Index)
 	var err error
+
+	if !opt.KeepSpaces {
+		s = strings.TrimSpace(s)
+	}
+
 	if opt.Type == Ptr {
 		err = opt.setPtrValue(fv, s)
 	} else if opt.Type == Slice {
 		err = opt.setSliceValue(fv, s)
 	} else {
 		err = value.Parse(fv.Addr().Interface(), s)
 	}
+
 	if err != nil {
 		err = fmt.Errorf("failed to set value for '%v': %w", opt.Name(), err)
 	}
@@ -190,6 +198,12 @@ func (opt *T) setSliceValue(fv reflect.Value, s string) error {
 	} else if opt.Sep != "" {
 		var updatedSlice = fv
 		for _, vs := range splitSliceValues(s, opt.Sep) {
+			if !opt.KeepSpaces {
+				vs = strings.TrimSpace(vs)
+			}
+			if !opt.KeepEmpty && vs == "" {
+				continue
+			}
 			var v = reflect.New(fv.Type().Elem())
 			if err := value.Parse(v.Interface(), vs); err != nil {
 				return err
@@ -264,6 +278,10 @@ func (opt *T) parseOptsTag(tag string) error {
 			opt.Sep = v
 		} else if k == "name" {
 			opt.ValueName = v
+		} else if k == "keep-spaces" {
+			opt.KeepSpaces = true
+		} else if k == "keep-empty" {
+			opt.KeepEmpty = true
 		} else {
 			return fmt.Errorf("invalid tag in opts: '%v'", k)
 		}