Enhanced REPL

The FakeDataDSL REPL now includes visual inspection, step-through debugging, and table formatting.

Quick Start

fake_data_dsl repl

Commands

Basic Commands

load <path> - Load schemas from file/directory
list - List loaded schemas
info <Schema> - Show schema details
gen <Schema> - Generate one record (JSON format)
gen <Schema> N - Generate N records (JSON format)
seed <number> - Set seed for deterministic output
mode <mode> - Set mode (random/edge/invalid/hostile/mixed)
help - Show help
quit / exit - Exit REPL

Enhanced Commands

table <Schema> - Generate one record (table view)
table <Schema> N - Generate N records (table view)
debug <Schema> - Step-through debugging
inspect <Schema> - Detailed inspection (table + JSON + statistics)

Table View

Display records in a formatted table:

> table User
  ────────────────────┼───────────────────────────────
  id                  │ "550e8400-e29b-41d4-a716-..."
  name                │ "John Doe"
  email               │ "john.doe@example.com"
  age                 │ 34

For multiple records:

> table User 5
  id                  │ name                │ email
  ────────────────────┼─────────────────────┼─────────────────────
  550e8400...         │ John Doe            │ john@example.com
  f47ac10b...         │ Jane Smith          │ jane@example.com
  ...

Step-Through Debugging

Debug generation field-by-field:

> debug User
🐛 Debug Mode: Generating User
Press Enter to continue after each field, 'q' to quit, 'c' to continue without pausing

[Field 1] id
────────────────────────────────────────────────────────
Value: "550e8400-e29b-41d4-a716-446655440000"

Context State:
  Depth: 0
  Registry: available
  Parent Context: no
  Shared Context: none

Generated Fields:
  (none yet)

Press Enter to continue, 'q' to quit, 'c' to continue without pausing: 

[Field 2] name
────────────────────────────────────────────────────────
Value: "John Doe"

Context State:
  Depth: 0
  Registry: available
  Parent Context: no
  Shared Context: none

Generated Fields:
  id                  = "550e8400-e29b-41d4-a716-446655440000"

Press Enter to continue, 'q' to quit, 'c' to continue without pausing: c
Continuing without pausing...

Debug Controls

Enter - Continue to next field
q / quit - Cancel debugging
c / continue - Continue without pausing

Detailed Inspection

Get comprehensive information about generated records:

> inspect User
📊 Generated Record:
============================================================
  ────────────────────┼───────────────────────────────
  id                  │ "550e8400-e29b-41d4-a716-..."
  name                │ "John Doe"
  email               │ "john.doe@example.com"
  age                 │ 34
  created_at          │ "2024-01-15T10:30:00Z"

📋 JSON Format:
{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "name": "John Doe",
  "email": "john.doe@example.com",
  "age": 34,
  "created_at": "2024-01-15T10:30:00Z"
}

📏 Statistics:
  Fields: 5
  Total size: 234 bytes
    id: String (36)
    name: String (8)
    email: String (20)
    age: Integer (2)
    created_at: String (20)

Examples

Loading Schemas

> load schemas/
✅ Loaded 3 schema(s)

> list
Loaded schemas:
  - User v1.0
  - Order v2.3
  - Product

Generating Data

> gen User
{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "name": "John Doe",
  "email": "john.doe@example.com"
}

> gen User 5
[
  { "id": "...", "name": "John Doe", ... },
  { "id": "...", "name": "Jane Smith", ... },
  ...
]

Using Seeds

> seed 42
✅ Seed set to 42

> gen User
{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  ...
}

> gen User  # Same seed = same output
{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  ...
}

Changing Modes

> mode edge
✅ Mode set to edge

> gen User
{
  "id": "00000000-0000-0000-0000-000000000000",
  "name": "",
  "email": ""
}

> mode hostile
✅ Mode set to hostile

> gen User
{
  "id": "' OR '1'='1",
  "name": "<script>alert(1)</script>",
  "email": "'; DROP TABLE users;--"
}

Use Cases

Debugging Complex Schemas

Use debug to understand how complex schemas with copy() and Ref() work:

> debug Order
# Step through each field to see context state
# Understand how copy() resolves parent fields
# See how Ref() resolves cross-schema references

Quick Data Inspection

Use table for quick visual inspection:

> table User 10
# See 10 users in a clean table format
# Easier to scan than JSON

Schema Exploration

Use inspect to understand schema output:

> inspect User
# See table + JSON + statistics
# Understand field types and sizes
# Verify schema structure

Tips

Use seeds for reproducibility - Set a seed to get consistent output
Use table view for quick checks - Faster than JSON for visual inspection
Use debug for complex schemas - Understand field dependencies
Use inspect for analysis - Get comprehensive information

Keyboard Shortcuts

Ctrl+C - Interrupt current operation
Ctrl+D - Exit REPL (same as quit)

Configuration

The REPL respects global configuration:

FakeDataDSL.configure do |config|
  config.default_mode = :edge
  config.limits.max_array_size = 100
end

Troubleshooting

No Output

Check that schemas are loaded:

> list
No schemas loaded. Use 'load <path>' first.

Schema Not Found

Verify schema name:

> list
Loaded schemas:
  - User
  - Order

> gen User  # Correct
> gen user  # Wrong (case-sensitive)
❌ Schema 'user' not found

Debug Mode Not Working

Ensure on_field_generated callback is available (it's built-in, should work automatically).