[error] Improve display of error messages (colours, auto-inferred file name and line number)

[forfudan]

This PR refactors Decimo’s error handling to produce Python-style tracebacks with ANSI coloring, and updates many call sites to raise typed DecimoError[...] variants (e.g., ValueError, OverflowError) with consistent metadata (message/function/previous error).

Changes:

• Reworked DecimoError formatting to mimic Python tracebacks, including chained errors and ANSI colors.
• Updated many modules to raise structured DecimoError variants instead of raw string Error(...) messages.
• Removed explicit file= parameters at many raise sites in favor of auto-captured file/line via call_location().

[Copilot]

Pull request overview

This PR refactors Decimo’s error handling to produce Python-style tracebacks with ANSI coloring, and updates many call sites to raise typed DecimoError[...] variants (e.g., ValueError, OverflowError) with consistent metadata (message/function/previous error).

Changes:

• Reworked DecimoError formatting to mimic Python tracebacks, including chained errors and ANSI colors.
• Updated many modules to raise structured DecimoError variants instead of raw string Error(...) messages.
• Removed explicit file= parameters at many raise sites in favor of auto-captured file/line via call_location().

Reviewed changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
src/decimo/toml/parser.mojo	Uses structured ValueError for parse errors (duplicate keys, invalid syntax).
src/decimo/tests.mojo	Wraps TOML parse failures in DecimoError with chaining.
src/decimo/str.mojo	Converts numeric parsing errors from strings to ValueError.
src/decimo/errors.mojo	Implements colored, Python-style traceback formatting and auto-captures file/line.
src/decimo/decimal128/special.mojo	Replaces string errors with ValueError/OverflowError for factorial operations.
src/decimo/decimal128/rounding.mojo	Uses OverflowError with improved messages for rounding overflow.
src/decimo/decimal128/exponential.mojo	Standardizes errors and chaining in power/root/exp/ln/log operations.
src/decimo/decimal128/decimal128.mojo	Updates constructors/conversions to use typed errors with chaining and clearer messages.
src/decimo/decimal128/constants.mojo	Uses ValueError for invalid constant selection inputs.
src/decimo/decimal128/arithmetics.mojo	Uses typed errors for overflow/div-by-zero and operation failures.
src/decimo/biguint/biguint.mojo	Removes manual file= fields and aligns exceptions to new auto-location behavior.
src/decimo/biguint/arithmetics.mojo	Updates div-by-zero and validation errors to typed errors.
src/decimo/bigint10/bigint10.mojo	Switches several conversion/overflow conditions to typed errors.
src/decimo/bigint10/arithmetics.mojo	Removes manual file= fields from chained DecimoError wrappers.
src/decimo/bigint/number_theory.mojo	Removes manual file= fields from DecimoError usage.
src/decimo/bigint/exponential.mojo	Removes manual file= fields from DecimoError usage.
src/decimo/bigint/bigint.mojo	Uses typed OverflowError/ValueError in conversions and power validation.
src/decimo/bigint/arithmetics.mojo	Uses ZeroDivisionError in division-by-zero path and removes manual file metadata.
src/decimo/bigfloat/bigfloat.mojo	Migrates MPFR-related failures to DecimoError/ConversionError.
src/decimo/bigdecimal/trigonometric.mojo	Uses ValueError for undefined trig edge cases.
src/decimo/bigdecimal/exponential.mojo	Uses typed errors for invalid power/root/log inputs and overflow cases.
src/decimo/bigdecimal/constants.mojo	Uses ValueError for invalid precision input.
src/decimo/bigdecimal/bigdecimal.mojo	Uses ValueError/ConversionError for scalar/Python Decimal conversion failures.
src/decimo/bigdecimal/arithmetics.mojo	Uses ZeroDivisionError for division/modulo-by-zero conditions.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.