Sequence Tool

The Sequence Tool extension for Visual Studio Code allows you to easily insert custom sequences with a live preview.

Features

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Insert Custom Sequence With Multi-cursors - sequence-tool.insertSequence

To insert a custom sequence using multi-cursors, use the following keyboard shortcut:

• Windows/Linux: Ctrl + Alt + 0,
• Mac: Cmd + Alt + 0

Note: Linebreak insertion is not supported with this command. Instead, use sequence-tool.insertNLinesAfter.

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Insert N Lines After Cursors - sequence-tool.insertNLinesAfter

This command allows you to insert N lines after the cursor(s) and creates N new cursors on each line inserted.

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Use Previous Saved Commands - sequence-tool.useCommand

You can defined custom commands from the settings sequence-tool.customCommands. These commands will be accessible through the sequence-tool.useCommand command and can be invoked via keybindings.

Example

1. Basic Usage

• To create a basic sequence, simply use the initial value:

  42           // 42, 43, 44, 45, ...
  

2. Padding

• Add padding to the sequence using the following syntax:

  #<5,42       // 42###, 43###, ...
  

3. Step

• To create a sequence with custom step size, use the third parameter:

  #<5,42,p+0.3 // 42.0#, 42.3#, 42.6#, ...
  

4. Base conversion

• Binary number with 0 padding uses 2's complement for negative numbers:

  04b,-3       // 1101, 1110, 1111, 0000, 0001, ...
  

• ASCII/Unicode representation:

  c,65         // A, B, C, D, E, ...
  

5. Other Practical Use

• Repeated character N times:

  #>3,,''      // ###, ###, ###, ...
  

• Cyclic and repeated values:

  ,,'123'[(i/4|0)%3] // 1,1,1,1, 2,2,2,2, 3,3,3,3, 1,...
  

• Spreadsheet column names:

  AZ           // AZ, BA, BB, BC, ...
  

• Early stopping:

  ,,i<5?p+1:'' // 0, 1, 2, 3, 4, 5 (index starts from 1 after init)
  

6. Custom Sequence

• Using the previous value in the sequence (similar to Array.prototype.reduce):

  ,1,p*2 (Power of 2)

• Cyclic pattern using an index (0-based):

  ,,['Sun','Mon','Tue','Wed','Thu','Fri','Sat'][i%7]

• Using both the previous value and index:

  ,1,p*(i+1) (factorial)

• Fibonacci sequence: d,,(((1+Math.sqrt(5))/2)**i-((1-Math.sqrt(5))/2)**i)/Math.sqrt(5)

• Catalan number: ,1,(4-6/(i+2))*p

  Alternatively: ,,(f=>f(f))(c=>x=>x?(4+6/~x)*(f=>f(f))(c)(x-1):1)(i)

• Look and say sequence: ,1,`${p}`.replace(/(.)\1*/g, m=>`${m.length}${m.substring(0, 1)}`)

Command Syntax

The extension supports a variety of formatting options using a subset of Python's format specification mini-language. The syntax for the command is as follows:

[[[fillChar]align][width][.prec][spec]],[init],[expr]

The command can either contain only the [init] field or separate the possibly empty field with ,.

Field	Definition
fillChar	Character used to pad to the given width. The alignment must be specified, excpet for fillChar=0.
align	Use > for right-align and < for left-align within the available space.
.prec	The number of digits to be displayed after the decimal point for the f spec.
spec	Specifies how the value should be displayed (refer to details below).
init	Initial value of sequence, defaults to 0 (see details below).
expr	The function (p, i) => expr generates the next value of the sequence. (see details below)

Spec

The spec field allows you to customize how the sequence values are displayed.

Here are some format specifiers:

Field	Definition
b	Binary number.
o	Octal number.
d	Decimal integer number.
h,x,H,X	Hexadecimal number, use H or X for uppercase digits.
f	Decimal fractional numbers.
c	Converts to single Unicode character.
b\d+	Convert to other bases, can be 2 to 36 (For example: b36 for base 36).

Init

Type	Definition
Number	Number literal, can be fractional.
English Letter	Generates the spreadsheet column name sequence.
JavaScript Expression	Any valid javascript expressions.

Expr

You can customize how the next value of the sequence is generated using the expr field. The function (p, i) => expr allows you to define the logic for generating the next value.

For example, to generate a sequence with a step size of 2, you can use (p, i) => p + 2.

Parameter	Definition
p	The previous value of the sequence, initalized by init.
i	Zero-based index of the sequence.

Extension Settings

This extension contributes the following settings:

• sequence-tool.customCommands: Store your frequently used commands here. These commands will appear in the sequence-tool.useCommand command and can be invoked through keybindings.

Example

Example Settings:

Item	Value
ascii uppercase	c,65,i<26?p+1:''
day of week	,,['Sun','Mon','Tue','Wed','Thu','Fri','Sat'][i%7]
factorial	,1,p*(i+1)
Fibonacci	d,,(((1+Math.sqrt(5))/2)**i-((1-Math.sqrt(5))/2)**i)/Math.sqrt(5)
Catalan	,1,(4-6/(i+2))*p
Look and say	,1,`${p}`.replace(/(.)\1*/g, m=>`${m.length}${m.substring(0, 1)}`)

Keybindings

You can invoke commands through custom keybindings. Access the keybindings JSON by selecting Preferences: Open Keyboard Shortcuts (JSON).

Example keybindings for the factorial command and the preconfigured Catalan number command:

// Execute a command (factorial) on keypress
{
   "key": "ctrl+alt+,",
   "command": "sequence-tool.insertSequence",
   "args": { "command": ",1,p*(i+1)" }
},
// Pick a preconfigured command (Catalan numbers) on keypress
{
  "key": "ctrl+alt+.",
  "command": "sequence-tool.useCommand",
  "args": { "name": "Catalan" }
}

Release Notes

See CHANGELOG.md.

Special Thanks!

• Special thanks to tomoki1207/vscode-input-sequence for the live preview functionality.