Add Native Code formatter

[notJoon]

Description

Implements native code formatting functionality similar to gofmt/gofumpt as a built-in feature.

Commands

Basic Format Command

tlin fmt [flags] [path...]

Formats the code in the specified paths. If no path is specified, it reads from stdin.

Flags

General Options

• -l, --list
  • List files that would be reformatted
  • Does not actually format the files
• -w, --write
  • Write formatted content to source files
  • Without this flag, prints to stdout
• -d, --diff
  • Display diffs of formatting changes
• -s, --simplify
  • Simplify code where possible (like gofumpt)

Style Options

• --indent-style=<tab|space>
  • Indentation style (default: tab)
• --indent-width=<n>
  • Number of spaces per indentation level when using spaces (default: 4)
• --line-length=<n>
  • Maximum line length (default: 100)
• --no-rewrite-imports
  • Disable import block rewriting/reordering

Examples

# Format a single file
tlin fmt file.gno

# Format and overwrite multiple files
tlin fmt -w file1.gno file2.gno

# Format all Go files in current directory and subdirectories
tlin fmt -w .

# Show formatting changes without applying them
tlin fmt -d file.gno

# List files that need formatting
tlin fmt -l .

# Format using spaces instead of tabs
tlin fmt --indent-style=space file.gno

# Format with simplified code style
tlin fmt -s file.gno

Behavior

Code Simplification (-s flag)

Integrate with auto fixer

When the -s flag is used, the formatter will apply additional simplifications similar to gofumpt:

1. Standardize empty lines

   • Single empty line between functions
   • No empty lines at start/end of block
   • Group related blocks with empty lines

2. Import blocks

   • Sort imports into groups (standard library, external, internal. related with: RFC: suggested import organization: separate by network or by purpose? gnolang/gno#3521)
   • Remove unnecessary parentheses in import blocks
   • Standardize import aliases

3. Code patterns

   • Remove redundant type declarations
   • Simplify redundant boolean expressions
   • Use short variable declarations where possible

Exit Codes

• 0: Success (no formatting changes needed or changes applied successfully)
• 1: Syntax errors in input
• 2: Usage error (invalid flags, etc.)

Configuration

The formatter can be configured through .tlin.yaml configuration file:

formatter:
  indent-style: tab
  indent-width: 4
  line-length: 100
  simplify: false
  rewrite-imports: true

Command line flags take precedence over configuration file settings.