Support default values for args (#4)

* Support default values for args

* Fix CI tests

.github/workflows/tests.yaml

@@ -33,4 +33,4 @@ jobs:
       - run: ./roc_nightly/roc version
 
       # run all tests 
-      - run: for f in **/*.roc; do ./roc_nightly/roc test $f; done
+      - run: ./roc_nightly/roc test package/main.roc

examples/default-values.roc

@@ -26,9 +26,22 @@ main =
 
 cliParser =
     { Cli.weave <-
-        alpha: Opt.maybeU64 { short: "a", long: "alpha", help: "Set the alpha level. [default: 123]" }
-        |> Cli.map \a -> Result.withDefault a 123,,
-        file: Param.maybeStr { name: "file", help: "The file to process. [default: NONE]" }
+        alpha: Opt.u64 {
+            short: "a",
+            long: "alpha",
+            help: "Set the alpha level. [default: 123]",
+            default: Value 123,
+        },
+        beta: Opt.dec {
+            short: "b",
+            long: "beta",
+            help: "Set the beta level. [default: PI]",
+            default: Generate (\{} -> Num.pi),
+        },
+        file: Param.maybeStr {
+            name: "file",
+            help: "The file to process. [default: NONE]",
+        }
         |> Cli.map \f -> Result.withDefault f "NONE",
     }
     |> Cli.finish {

examples/subcommands.roc

@@ -9,7 +9,7 @@ import pf.Task exposing [Task]
 import weaver.Opt
 import weaver.Cli
 import weaver.Param
-import weaver.Subcommand
+import weaver.SubCmd
 
 main =
     args = Arg.list!
@@ -28,7 +28,7 @@ main =
 cliParser =
     { Cli.weave <-
         force: Opt.flag { short: "f", help: "Force the task to complete." },
-        sc: Subcommand.optional [subcommandParser1, subcommandParser2],
+        sc: SubCmd.optional [subcommandParser1, subcommandParser2],
         file: Param.maybeStr { name: "file", help: "The file to process." },
         files: Param.strList { name: "files", help: "The rest of the files." },
     }
@@ -44,14 +44,14 @@ subcommandParser1 =
     { Cli.weave <-
         d: Opt.maybeU64 { short: "d", help: "A non-overlapping subcommand flag with s2." },
         volume: Opt.maybeU64 { short: "v", long: "volume", help: "How loud to grind the gears." },
-        sc: Subcommand.optional [subSubcommandParser1, subSubcommandParser2],
+        sc: SubCmd.optional [subSubcommandParser1, subSubcommandParser2],
     }
-    |> Subcommand.finish { name: "s1", description: "A first subcommand.", mapper: S1 }
+    |> SubCmd.finish { name: "s1", description: "A first subcommand.", mapper: S1 }
 
 subcommandParser2 =
     Opt.maybeU64 { short: "d", help: "This doesn't overlap with s1's -d flag." }
     |> Cli.map DFlag
-    |> Subcommand.finish {
+    |> SubCmd.finish {
         name: "s2",
         description: "Another subcommand.",
         mapper: S2,
@@ -62,12 +62,12 @@ subSubcommandParser1 =
         a: Opt.u64 { short: "a", help: "An example short flag for a sub-subcommand." },
         b: Opt.u64 { short: "b", help: "Another example short flag for a sub-subcommand." },
     }
-    |> Subcommand.finish { name: "ss1", description: "A sub-subcommand.", mapper: SS1 }
+    |> SubCmd.finish { name: "ss1", description: "A sub-subcommand.", mapper: SS1 }
 
 subSubcommandParser2 =
     { Cli.weave <-
         a: Opt.u64 { short: "a", help: "Set the alpha level." },
         c: Opt.u64 { short: "c", long: "create", help: "Create a doohickey." },
         data: Param.str { name: "data", help: "Data to manipulate." },
     }
-    |> Subcommand.finish { name: "ss2", description: "Another sub-subcommand.", mapper: SS2 }
+    |> SubCmd.finish { name: "ss2", description: "Another sub-subcommand.", mapper: SS2 }

package/Base.roc

@@ -13,14 +13,19 @@ module [
     Plurality,
     SpecialFlags,
     InvalidValue,
+    DefaultValue,
     ValueParser,
     OptionConfigBaseParams,
+    DefaultableOptionConfigBaseParams,
     OptionConfigParams,
+    DefaultableOptionConfigParams,
     OptionConfig,
     helpOption,
     versionOption,
     ParameterConfigBaseParams,
+    DefaultableParameterConfigBaseParams,
     ParameterConfigParams,
+    DefaultableParameterConfigParams,
     ParameterConfig,
     CliConfigParams,
     CliConfig,
@@ -110,6 +115,8 @@ SpecialFlags : { help : Bool, version : Bool }
 
 InvalidValue : [InvalidNumStr, InvalidValue Str]
 
+DefaultValue a : [NoDefault, Value a, Generate ({} -> a)]
+
 ## A parser that extracts an argument value from a string.
 ValueParser a : Str -> Result a InvalidValue
 
@@ -119,6 +126,13 @@ OptionConfigBaseParams : {
     help ? Str,
 }
 
+DefaultableOptionConfigBaseParams a : {
+    short ? Str,
+    long ? Str,
+    help ? Str,
+    default ? DefaultValue a,
+}
+
 ## Default-value options for creating an option.
 OptionConfigParams a : {
     short ? Str,
@@ -128,6 +142,16 @@ OptionConfigParams a : {
     parser : ValueParser a,
 }
 
+## Default-value options for creating an option.
+DefaultableOptionConfigParams a : {
+    short ? Str,
+    long ? Str,
+    help ? Str,
+    type : Str,
+    parser : ValueParser a,
+    default ? DefaultValue a,
+}
+
 ## Metadata for options in our CLI building system.
 OptionConfig : {
     expectedValue : ExpectedValue,
@@ -162,6 +186,12 @@ ParameterConfigBaseParams : {
     help ? Str,
 }
 
+DefaultableParameterConfigBaseParams a : {
+    name : Str,
+    help ? Str,
+    default ? DefaultValue a,
+}
+
 ## Default-value options for creating an parameter.
 ParameterConfigParams a : {
     name : Str,
@@ -170,6 +200,15 @@ ParameterConfigParams a : {
     parser : ValueParser a,
 }
 
+## Default-value options for creating an parameter.
+DefaultableParameterConfigParams a : {
+    name : Str,
+    help ? Str,
+    type : Str,
+    parser : ValueParser a,
+    default ? DefaultValue a,
+}
+
 ## Metadata for parameters in our CLI building system.
 ParameterConfig : {
     name : Str,

package/Builder.roc

@@ -89,20 +89,20 @@ setParser = \@CliBuilder builder, parser ->
 updateParser : CliBuilder state fromAction toAction, ({ data : state, remainingArgs : List Arg } -> Result { data : nextState, remainingArgs : List Arg } ArgExtractErr) -> CliBuilder nextState fromAction toAction
 updateParser = \@CliBuilder builder, updater ->
     newParser =
-        { data, remainingArgs, subcommandPath } <- onSuccessfulArgParse builder.parser
-        when updater { data, remainingArgs } is
-            Err err -> IncorrectUsage err { subcommandPath }
-            Ok { data: updatedData, remainingArgs: restOfArgs } ->
-                SuccessfullyParsed { data: updatedData, remainingArgs: restOfArgs, subcommandPath }
+        onSuccessfulArgParse builder.parser \{ data, remainingArgs, subcommandPath } ->
+            when updater { data, remainingArgs } is
+                Err err -> IncorrectUsage err { subcommandPath }
+                Ok { data: updatedData, remainingArgs: restOfArgs } ->
+                    SuccessfullyParsed { data: updatedData, remainingArgs: restOfArgs, subcommandPath }
 
     setParser (@CliBuilder builder) newParser
 
 bindParser : CliBuilder state fromAction toAction, (ArgParserState state -> ArgParserResult (ArgParserState nextState)) -> CliBuilder nextState fromAction toAction
 bindParser = \@CliBuilder builder, updater ->
     newParser : ArgParser nextState
     newParser =
-        { data, remainingArgs, subcommandPath } <- onSuccessfulArgParse builder.parser
-        updater { data, remainingArgs, subcommandPath }
+        onSuccessfulArgParse builder.parser \{ data, remainingArgs, subcommandPath } ->
+            updater { data, remainingArgs, subcommandPath }
 
     setParser (@CliBuilder builder) newParser
 

package/Cli.roc

@@ -1,9 +1,9 @@
-## Weave together a CLI parser using the `<- ` builder notation!
+## Weave together a CLI parser using the `<-` builder notation!
 ##
 ## This module is the entry point for creating CLIs using Weaver.
 ## To get started, call the [weave] method and pass a
 ## [record builder](https://www.roc-lang.org/examples/RecordBuilder/README.html)
-## to it. You can pass `Opt`s, `Param`s, or `Subcommand`s as fields,
+## to it. You can pass `Opt`s, `Param`s, or `SubCmd`s as fields,
 ## and Weaver will automatically register them in its config as
 ## well as build a parser with the inferred types of the fields
 ## you set.
@@ -28,7 +28,7 @@
 ## ```roc
 ## fooSubcommand =
 ##     Opt.u64 { short: "a", help: "Set the alpha level" }
-##     |> Subcommand.finish {
+##     |> SubCmd.finish {
 ##         name: "foo",
 ##         description: "Foo some stuff."
 ##         mapper: Foo,
@@ -38,15 +38,15 @@
 ##     # We allow two subcommands of the same parent to have overlapping
 ##     # fields since only one can ever be parsed at a time.
 ##     Opt.u64 { short: "a", help: "Set the alpha level" }
-##     |> Subcommand.finish {
+##     |> SubCmd.finish {
 ##         name: "bar",
 ##         description: "Bar some stuff."
 ##         mapper: Bar,
 ##     }
 ##
 ## { Cli.weave <-
 ##     verbosity: Opt.count { short: "v", long: "verbose" },
-##     sc: Subcommand.optional [fooSubcommand, barSubcommand],
+##     sc: SubCmd.optional [fooSubcommand, barSubcommand],
 ## }
 ## ```
 ##
@@ -85,8 +85,8 @@
 ## If you want to see more examples, check the [examples](https://github.com/smores56/weaver/tree/main/examples)
 ## folder in the [repository](https://github.com/smores56/weaver).
 ##
-## _note: `Opt`s must be set before an optional `Subcommand` field is given,_
-## _and the `Subcommand` field needs to be set before `Param`s are set._
+## _note: `Opt`s must be set before an optional `SubCmd` field is given,_
+## _and the `SubCmd` field needs to be set before `Param`s are set._
 ## _`Param` lists also cannot be followed by anything else including_
 ## _themselves. These requirements ensure we parse arguments in the_
 ## _right order. Luckily, all of this is ensured at the type level._
@@ -149,7 +149,7 @@ map : CliBuilder a fromAction toAction, (a -> b) -> CliBuilder b fromAction toAc
 map = \builder, mapper ->
     Builder.map builder mapper
 
-## Begin weaving together a CLI builder using the `<- ` builder notation.
+## Begin weaving together a CLI builder using the `<-` builder notation.
 ##
 ## Check the module-level documentation for general usage instructions.
 ##