Go Function Analysis

Overview

This skill analyzes all Go functions in a workspace and generates:

1. A complete list of functions with their line counts and maximum call depths
2. Statistical analysis (p50, p90, p99 percentiles)

When to Use

Use this skill when:

• Auditing code complexity in a Go project
• Identifying long functions that may need refactoring
• Generating code metrics for documentation
• Reviewing function size distribution

How to Execute

Step 1: Find All Go Files

Find all .go files in the workspace, excluding common dependency directories:

find . -name "*.go" -type f ! -path "./vendor/*" ! -path "./.git/*" ! -path "*_test.go"

Step 2: Extract Functions and Calculate Lengths

For each .go file, use the helper script to extract function information:

./scripts/analyze_functions.sh <workspace_path>

Or manually parse using this approach for each file:

1. Find all function declarations with line numbers
2. For each function, count lines from func declaration to matching closing brace
3. Record: file path, function name, start line, end line, total lines

Step 3: Calculate Percentiles

Given all function lengths sorted ascending:

• p50 (median): Value at position count * 0.50
• p90: Value at position count * 0.90
• p99: Value at position count * 0.99

Step 4: Generate README.function.md

Create README.function.md in the workspace root with this format:

# Go Function Analysis

Generated: YYYY-MM-DD

## Summary Statistics

| File Path | Function Name | Function Lines | Depth Level | Percentile |
| --------- | ------------- | -------------- | ----------- | ---------- |
| path/to/f | funcName      | X              | Y           | p50        |
| ...       | ...           | ...            | ...         | ...        |

**Total functions:** N
**Average length:** X lines

## All Functions (sorted by length, descending)

| File Path | Function Name | Function Lines | Depth Level |
| --------- | ------------- | -------------- | ----------- |
| path/to/f | funcName      | X              | Y           |
| ...       | ...           | ...            | ...         |

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Manual Analysis Approach

If the script is not available, follow these steps:

Finding Functions in Go

Go functions are declared with:

func FunctionName(params) returnType {
    // body
}

func (receiver Type) MethodName(params) returnType {
    // body
}

Counting Lines

For each function:

1. Start from the func keyword line
2. Count until the matching closing }
3. Include the func and } lines in the count

Example

func example() {     // Line 1
    fmt.Println()    // Line 2
    if true {        // Line 3
        doSomething()// Line 4
    }                // Line 5
}                    // Line 6

This function has 6 lines.

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Important Notes

[!NOTE] Only analyze .go files within the workspace. Exclude /vendor/, /.git/, and external dependencies.

[!TIP] Functions over 50 lines may be candidates for refactoring. p90+ functions often warrant closer review.