26.1 by thatstoasty · Pull Request #62 · thatstoasty/prism

thatstoasty · 2026-02-18T23:54:03Z

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Copilot

Pull request overview

This pull request upgrades the Prism library from Mojo 0.25.7 to 0.26.1, involving extensive API changes, breaking changes, and modernization of the codebase to align with the new Mojo version. The PR includes dependency updates, removal of deprecated utility scripts, significant refactoring of core types, and updates to all examples.

Changes:

Upgraded Mojo from 0.25.7 to 0.26.1 and mog from 25.7.0 to 26.1.2
Replaced alias with comptime throughout the codebase for type definitions and constants
Consolidated command function types by removing raising_* variants; all functions now use CmdFn with raises
Changed Command.children parameter from List[ArcPointer[Self]] to List[Self] for simplified API
Removed Movable trait from multiple core structs
Updated method signatures to use Some[Writer] instead of generic [W: Writer] parameters
Removed utility scripts and Python-based docstring checker in favor of native Mojo tooling
Commented out flag action execution, which may break existing functionality

Reviewed changes

Copilot reviewed 36 out of 38 changed files in this pull request and generated 22 comments.

Show a summary per file

File	Description
pixi.toml	Updated Mojo version constraints from 0.25.7 to 0.26.1, mog from 25.7.0 to 26.1.2, changed package version to 0.1.0
pixi.lock	Regenerated lock file with updated package versions and dependency tree
README.md	Updated Mojo version badge from 25.7 to 26.1
scripts/util.mojo	Deleted utility script for running files
scripts/check-docstrings.py	Deleted Python script; replaced with native `mojo doc` command
scripts/examples.sh	Added `-D ASSERT=all` flag to all build commands; commented out complex examples
prism/writer.mojo	Changed `alias WriterFn` to `comptime WriterFn`
prism/version.mojo	Changed to `comptime`, removed `Movable` trait, removed `copy()` method
prism/suggest.mojo	Updated string comparisons from character access to slicing; changed return types from `StringSlice` to `String`
prism/help.mojo	Changed to `comptime`, removed `Movable` and copy methods, updated `set_width` to `width`
prism/flag.mojo	Major refactor: `FType.value` from `String` to `UInt8`, removed `Movable` trait, changed list flag defaults from `Optional[List[T]]` to `List[T]`, updated `write_to` signature
prism/exit.mojo	Changed `alias` to `comptime`
prism/command.mojo	Critical changes: made `run` required (not Optional), removed all `raising_*` variants, changed `parent` type, changed `children` parameter type, commented out flag action execution and large copy method
prism/args.mojo	Commented out `match_all` function entirely
prism/_util.mojo	Changed `panic` from generic to `Some[Writable]` parameter
prism/_flag_set.mojo	Changed getter methods to accept `StringSlice`, added `where` clauses, updated error message construction, changed `Float64(value)` parsing
prism/_flag_parser.mojo	Introduced new result structs replacing tuples for better clarity
prism/_flag_group.mojo	Minor formatting changes in error messages
prism/_arg_parse.mojo	Updated `STDINParserState` traits and renamed `input` parameter to `str`
examples/*.mojo	Updated all examples to use new API: removed `ArcPointer` wrappers, changed `raising_run` to `run`, updated list literal syntax
examples/requests/pixi.toml	Changed to use local path dependency for prism
examples/printer/pixi.toml	Converted to workspace format with pixi-build backend
.pre-commit-config.yaml	Commented out mojo-format hook
.gitignore	Added `kgen.*` pattern

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Copilot · 2026-02-19T00:02:05Z

prism/_util.mojo



-fn panic[W: Writable, //](message: W, code: Int = 1) -> None:
+fn panic(message: Some[Writable], code: Int = 1) -> None:


The panic function has changed from a generic panic[W: Writable, //] to panic(message: Some[Writable], ...). This changes from compile-time generics to runtime trait objects, which may have performance implications for error handling paths.

Suggested change

fn panic(message: Some[Writable], code: Int = 1) -> None:

fn panic[W: Writable](message: W, code: Int = 1) -> None:

Copilot · 2026-02-19T00:02:05Z

prism/_flag_set.mojo

        var floats = List[Float64](capacity=len(result.value()))
        for value in result.value():
-            floats.append(atof(value))
+            floats.append(Float64(value))


The conversion from Float64 to String using atof has been replaced with Float64(value) on line 829. This changes the parsing behavior and may have different error handling or precision characteristics. Ensure this change is intentional and doesn't break existing functionality.

Suggested change

floats.append(Float64(value))

floats.append(atof(value))

Copilot · 2026-02-19T00:02:05Z

prism/command.mojo

    var pre_run: Optional[CmdFn]
    """A function to run before the run function is executed."""
-    var run: Optional[CmdFn]
+    var run: CmdFn


The run field is now a required parameter (changed from Optional[CmdFn] to CmdFn). This is a breaking API change that removes the ability to have commands without a run function. Previously, commands could exist without a run function if they only served as parent commands for subcommands. This change forces all commands to have a run function, which may not be desirable for organizational/structural commands that only group subcommands.

Suggested change

var run: CmdFn

var run: Optional[CmdFn]

Copilot · 2026-02-19T00:02:06Z

prism/command.mojo

    """Child commands."""
    # TODO: An optional pointer would be great, but it breaks the compiler. So a list of 0-1 pointers is used.
-    var parent: List[ArcPointer[Self]]
+    var parent: ArcPointer[Optional[Self]]


The parent field has changed from List[ArcPointer[Self]] (0-1 elements) to ArcPointer[Optional[Self]]. While this is a cleaner design, it's a breaking change for any code that directly accessed the parent field. The comment on line 155 acknowledges that an optional pointer would be ideal but "breaks the compiler," suggesting this is a workaround for compiler limitations.

Copilot · 2026-02-19T00:02:06Z

prism/args.mojo

+# fn match_all[*arg_validators: ArgValidatorFn]() -> ArgValidatorFn:
+#     """Returns an error if any of the arg_validators return an error.

-    Parameters:
-        arg_validators: A list of ArgValidatorFn functions that check the arguments.
+#     Parameters:
+#         arg_validators: A list of ArgValidatorFn functions that check the arguments.

-    Returns:
-        A function that checks all the arguments using the arg_validators list.
-    """
+#     Returns:
+#         A function that checks all the arguments using the arg_validators list.
+#     """

-    fn match_all_args(args: List[String], valid_args: List[String]) raises -> None:
-        @parameter
-        for validator in VariadicList(arg_validators):
-            validator(args, valid_args)
+#     fn match_all_args(args: List[String], valid_args: List[String]) raises -> None:
+#         @parameter
+#         for validator in VariadicList(arg_validators):
+#             validator(args, valid_args)

-    return match_all_args
+#     return match_all_args


The match_all function has been commented out entirely (lines 120-135), removing functionality that allowed combining multiple argument validators. This is a breaking change that removes a useful feature without providing an alternative implementation or migration path.

Copilot · 2026-02-19T00:02:09Z

prism/_flag_set.mojo

@@ -457,7 +455,7 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):

        return flag.value()[].value_or_default()

-    fn get_bool(self, name: String) raises -> Optional[Bool]:
+    fn get_bool(self, name: StringSlice) raises -> Optional[Bool]:
        """Returns the value of a flag as a `Bool`. If it isn't set, then return the default value.

        Args:
@@ -479,7 +477,7 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):

        return string_to_bool(result.value())

-    fn get_int[type: FType = FType.Int](self, name: String) raises -> Optional[Int]:
+    fn get_int[type: FType = FType.Int](self, name: StringSlice) raises -> Optional[Int] where type.is_int_type():
        """Returns the value of a flag as an `Int`. If it isn't set, then return the default value.

        Parameters:
@@ -494,12 +492,6 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
-        constrained[
-            type.is_int_type(),
-            "type must be one of `Int`, `Int8`, `Int16`, `Int32`, `Int64`, `UInt`, `UInt8`, `UInt16`, `UInt32`, or"
-            " `UInt64`. Received: "
-            + type.value,
-        ]()
        var flag = self.lookup[type](name)
        if not flag:
            return None
@@ -509,7 +501,7 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
            return None
        return atol(result.value())

-    fn get_int8(self, name: String) raises -> Optional[Int8]:
+    fn get_int8(self, name: StringSlice) raises -> Optional[Int8]:
        """Returns the value of a flag as a `Int8`. If it isn't set, then return the default value.

        Args:
@@ -521,12 +513,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.Int8.is_int_type()
        var result = self.get_int[FType.Int8](name)
        if not result:
            return None
        return Int8(result.value())

-    fn get_int16(self, name: String) raises -> Optional[Int16]:
+    fn get_int16(self, name: StringSlice) raises -> Optional[Int16]:
        """Returns the value of a flag as a `Int16`. If it isn't set, then return the default value.

        Args:
@@ -538,12 +531,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.Int16.is_int_type()
        var result = self.get_int[FType.Int16](name)
        if not result:
            return None
        return Int16(result.value())

-    fn get_int32(self, name: String) raises -> Optional[Int32]:
+    fn get_int32(self, name: StringSlice) raises -> Optional[Int32]:
        """Returns the value of a flag as a `Int32`. If it isn't set, then return the default value.

        Args:
@@ -555,12 +549,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.Int32.is_int_type()
        var result = self.get_int[FType.Int32](name)
        if not result:
            return None
        return Int32(result.value())

-    fn get_int64(self, name: String) raises -> Optional[Int64]:
+    fn get_int64(self, name: StringSlice) raises -> Optional[Int64]:
        """Returns the value of a flag as a `Int64`. If it isn't set, then return the default value.

        Args:
@@ -572,12 +567,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.Int64.is_int_type()
        var result = self.get_int[FType.Int64](name)
        if not result:
            return None
        return Int64(result.value())

-    fn get_uint(self, name: String) raises -> Optional[UInt]:
+    fn get_uint(self, name: StringSlice) raises -> Optional[UInt]:
        """Returns the value of a flag as a `UInt`. If it isn't set, then return the default value.

        Args:
@@ -589,12 +585,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.UInt.is_int_type()
        var result = self.get_int[FType.UInt](name)
        if not result:
            return None
        return UInt(result.value())

-    fn get_uint8(self, name: String) raises -> Optional[UInt8]:
+    fn get_uint8(self, name: StringSlice) raises -> Optional[UInt8]:
        """Returns the value of a flag as a `UInt8`. If it isn't set, then return the default value.

        Args:
@@ -606,12 +603,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.UInt8.is_int_type()
        var result = self.get_int[FType.UInt8](name)
        if not result:
            return None
        return UInt8(result.value())

-    fn get_uint16(self, name: String) raises -> Optional[UInt16]:
+    fn get_uint16(self, name: StringSlice) raises -> Optional[UInt16]:
        """Returns the value of a flag as a `UInt16`. If it isn't set, then return the default value.

        Args:
@@ -623,12 +621,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.UInt16.is_int_type()
        var result = self.get_int[FType.UInt16](name)
        if not result:
            return None
        return UInt16(result.value())

-    fn get_uint32(self, name: String) raises -> Optional[UInt32]:
+    fn get_uint32(self, name: StringSlice) raises -> Optional[UInt32]:
        """Returns the value of a flag as a `UInt32`. If it isn't set, then return the default value.

        Args:
@@ -640,12 +639,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.UInt32.is_int_type()
        var result = self.get_int[FType.UInt32](name)
        if not result:
            return None
        return UInt32(result.value())

-    fn get_uint64(self, name: String) raises -> Optional[UInt64]:
+    fn get_uint64(self, name: StringSlice) raises -> Optional[UInt64]:
        """Returns the value of a flag as a `UInt64`. If it isn't set, then return the default value.

        Args:
@@ -657,12 +657,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.UInt64.is_int_type()
        var result = self.get_int[FType.UInt64](name)
        if not result:
            return None
        return UInt64(result.value())

-    fn get_float[type: FType](self, name: String) raises -> Optional[Float64]:
+    fn get_float[type: FType](self, name: StringSlice) raises -> Optional[Float64] where type.is_float_type():
        """Returns the value of a flag as a `Float64`. If it isn't set, then return the default value.

        Parameters:
@@ -677,9 +678,7 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
-        constrained[
-            type.is_float_type(), "type must be one of `Float16`, `Float32`, `Float64`. Received: " + type.value
-        ]()
+        __comptime_assert type.is_float_type()
        var flag = self.lookup[type](name)
        if not flag:
            return None
@@ -689,7 +688,7 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
            return None
        return atof(result.value())

-    fn get_float16(self, name: String) raises -> Optional[Float16]:
+    fn get_float16(self, name: StringSlice) raises -> Optional[Float16]:
        """Returns the value of a flag as a `Float16`. If it isn't set, then return the default value.

        Args:
@@ -701,12 +700,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.Float16.is_float_type()
        var result = self.get_float[FType.Float16](name)
        if not result:
            return None
        return result.value().cast[DType.float16]()

-    fn get_float32(self, name: String) raises -> Optional[Float32]:
+    fn get_float32(self, name: StringSlice) raises -> Optional[Float32]:
        """Returns the value of a flag as a `Float32`. If it isn't set, then return the default value.

        Args:
@@ -718,12 +718,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.Float32.is_float_type()
        var result = self.get_float[FType.Float32](name)
        if not result:
            return None
        return result.value().cast[DType.float32]()

-    fn get_float64(self, name: String) raises -> Optional[Float64]:
+    fn get_float64(self, name: StringSlice) raises -> Optional[Float64]:
        """Returns the value of a flag as a `Float64`. If it isn't set, then return the default value.

        Args:
@@ -735,12 +736,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.Float64.is_float_type()
        var result = self.get_float[FType.Float64](name)
        if not result:
            return None
        return result.value()

-    fn _get_list[type: FType](self, name: String) raises -> Optional[List[String]]:
+    fn _get_list[type: FType](self, name: StringSlice) raises -> Optional[List[String]] where type.is_list_type():
        """Returns the value of a flag as a `List[String]`. If it isn't set, then return the default value.

        Parameters:
@@ -755,10 +757,6 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
-        constrained[
-            type.is_list_type(),
-            "type must be one of `StringList`, `IntList`, or `Float64List`. Received: " + type.value,
-        ]()
        var flag = self.lookup[type](name)
        if not flag:
            return None
@@ -769,7 +767,7 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):

        return Optional([String(item) for item in result.value().split(sep=" ")])

-    fn get_string_list(self, name: String) raises -> Optional[List[String]]:
+    fn get_string_list(self, name: StringSlice) raises -> Optional[List[String]]:
        """Returns the value of a flag as a `List[String]`. If it isn't set, then return the default value.

        Args:
@@ -781,12 +779,13 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.StringList.is_list_type()
        var result = self._get_list[FType.StringList](name)
        if not result:
            return None
        return result^

-    fn get_int_list(self, name: String) raises -> Optional[List[Int]]:
+    fn get_int_list(self, name: StringSlice) raises -> Optional[List[Int]]:
        """Returns the value of a flag as a `List[Int]`. If it isn't set, then return the default value.

        Args:
@@ -798,6 +797,7 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
        Raises:
            Error: If the flag is not found.
        """
+        __comptime_assert FType.IntList.is_list_type()
        var result = self._get_list[FType.IntList](name)
        if not result:
            return None
@@ -807,7 +807,7 @@ struct FlagSet(Boolable, Copyable, Movable, Sized, Stringable, Writable):
            ints.append(atol(value))
        return ints^

-    fn get_float64_list(self, name: String) raises -> Optional[List[Float64]]:
+    fn get_float64_list(self, name: StringSlice) raises -> Optional[List[Float64]]:


All getter methods in FlagSet now accept StringSlice instead of String for the name parameter (e.g., lines 443, 458, 480). This is more efficient as it avoids unnecessary String allocations, but it's a breaking change for existing code passing String literals or String variables.

Copilot · 2026-02-19T00:02:09Z

prism/_flag_set.mojo

+                raise Error(
+                    "FlagSet.from_args: Failed to set flag, ",
+                    name,
+                    ", with value: ",
+                    value,
+                    ". Flag could not be found.",
                )


The error message construction has been changed from using StaticString.format() (line 162-169) to string concatenation. While this is simpler, it loses the formatting capability and may be less efficient for complex error messages. The change appears to be consistent with removing StaticString usage throughout the codebase.

Copilot · 2026-02-19T00:02:09Z

prism/command.mojo

        var valid_args: List[String] = [],
-        var children: List[ArcPointer[Self]] = [],
-        run: Optional[CmdFn] = None,
+        var children: List[Self] = [],


The children parameter type has changed from List[ArcPointer[Self]] to List[Self] in the constructor, but the internal storage still uses List[ArcPointer[Self]]. While the conversion logic exists (lines 238-240), this is a breaking API change for existing code that passes ArcPointer wrapped children. Users now need to pass unwrapped Command instances directly.

Suggested change

var children: List[Self] = [],

var children: List[ArcPointer[Self]] = [],

Copilot · 2026-02-19T00:02:09Z

prism/flag.mojo

        usage: StringSlice,
        shorthand: String = "",
-        default: Optional[List[String]] = None,
+        default: List[String] = [],


The default parameters for list flag constructors have changed from Optional[List[T]] to List[T]. For example, default: Optional[List[String]] = None is now default: List[String] = []. While this simplifies the API by removing the Optional wrapper, it's a breaking change that requires updating all call sites. The empty list default [] may also have different semantics than None in some contexts.

Copilot · 2026-02-19T00:02:09Z

prism/flag.mojo

@@ -112,7 +77,7 @@ struct FType(Copyable, EqualityComparable, ImplicitlyCopyable, Movable):
 # TODO: When we have trait objects, switch to using actual flag structs per type instead of
 # needing to cast values to and from string.
 @fieldwise_init
-struct Flag(Copyable, Movable, Representable, Stringable, Writable):
+struct Flag(Copyable, Representable, Stringable, Writable):


The Movable trait has been removed from several structs including FType, Flag, FlagSet, Command, Help, and Version. Removing Movable could impact performance since move semantics won't be available for these types. This may force more copies in certain scenarios.

thatstoasty added 3 commits January 29, 2026 12:22

checkpoint

f836c89

get it working again

d9764ff

update readme

dbdd33a

Copilot AI review requested due to automatic review settings February 18, 2026 23:54

Copilot started reviewing on behalf of thatstoasty February 18, 2026 23:54 View session

thatstoasty merged commit cb127ba into main Feb 18, 2026
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thatstoasty deleted the 26.1 branch February 18, 2026 23:59

Copilot AI reviewed Feb 19, 2026

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26.1#62

26.1#62
thatstoasty merged 3 commits intomainfrom
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		fn panic[W: Writable, //](message: W, code: Int = 1) -> None:
		fn panic(message: Some[Writable], code: Int = 1) -> None:

	fn panic(message: Some[Writable], code: Int = 1) -> None:
	fn panic[W: Writable](message: W, code: Int = 1) -> None:

	var children: List[Self] = [],
	var children: List[ArcPointer[Self]] = [],

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