hashline-edit

name	hashline-edit
description	Content-addressed line editing using hashline tags. Use when editing files where exact text reproduction is unreliable. Hashlines provide stable anchors: "42:a3|content" → edit by referencing "42:a3".
version	1.0.0
triggers	["hashline","content-addressed","stable-edit"]
lambda	hashline.edit.content-addressed
metadata	{"evolution-stats":{"total-experiments":0}}
level	atom

hashline-edit: Content-Addressed Line Editing

When to Use

Use hashline editing when:

• Edit tool fails with "oldString not found" due to formatting differences
• File has complex whitespace/indentation that's hard to reproduce exactly
• You need to edit a file that might change between read and edit
• Working with files that have variable formatting (e.g., generated code)

Prefer hashline over string mode — it's more reliable.

How It Works

1. Read with hashline=true

Read(file_path="src.el", hashline=true)

Returns:

1:a3|(defun hello ()
2:f1|  "world")

2. Edit by hash tag

Edit(file_path="src.el", old_str="2:f1", new_str="  \"universe\"")

No need to reproduce exact text or whitespace!

Hashline Formats

Single Line

Edit(file_path="file", old_str="42:a3", new_str="replacement")

Range Replacement

Edit(file_path="file", old_str="2:f1 to 5:b2", new_str="new lines here")

Insert After

Edit(file_path="file", old_str="+2:f1", new_str="inserted line")

Decision Tree

IF file was read with hashline=true:
  → Use hashline mode (pass hash tag as old_str)
ELIF change is simple AND exact text is known:
  → Use string mode
ELIF multiple changes needed:
  → Use patch mode (diffp=true)

Anti-Patterns

• ❌ Reproducing text when hashline tags are available
• ❌ Using string mode for files with complex formatting
• ❌ Not using hashline=true when planning to edit

Examples

Example 1: Simple Replacement

Read:

Read(file_path="config.json", hashline=true)
→ 10:a3|  "timeout": 30,

Edit:

Edit(file_path="config.json", old_str="10:a3", new_str='  "timeout": 60,')

Example 2: Range Replacement

Read:

Read(file_path="main.py", hashline=true)
→ 42:a3|def old_function():
→ 43:f1|    pass
→ 44:0e|

Edit:

Edit(file_path="main.py", old_str="42:a3 to 44:0e",
     new_str="def new_function():\n    return True")

Example 3: Insert After

Read:

Read(file_path="routes.py", hashline=true)
→ 15:a3|@app.route('/api/v1')

Edit:

Edit(file_path="routes.py", old_str="+15:a3",
     new_str="@app.route('/api/v2')")

Safety

• Optimistic locking: Hash mismatch → edit rejected before corruption
• Content addressing: If file changed since read, hash won't match
• No truncation: Unlike string mode, no risk of partial matches

Integration

Read(file_path="target.el", hashline=true)
→ Returns hashline-tagged content

Edit(file_path="target.el", old_str="42:a3", new_str="...")
→ Verifies hash before editing
→ Returns success or hash mismatch error