[Question]
  [
Write a piece of code that takes a string as input, and outputs a piece of code in the **same language** that, when run, will output the initial input string.
It must be able to handle any combination of characters A-Z, a-z, and 0-9.
Example in Python:
```
import sys
print "print('" + sys.argv[1]  + "')"
```
Given the input of `testing123`, it will return `print('testing123')`.
Since this is [code-golf](/questions/tagged/code-golf "show questions tagged 'code-golf'"), the shortest answer in bytes will win.
  
[Answer]
# [pl](https://github.com/quartata/pl-lang), 0 bytes
### Code:
[Try it online!](https://tio.run/##K8j5DwQlqcUlAA "pl ‚Äì Try It Online")
### Explanation:
An empty program in pl is simply a cat program, outputting the exact same as the input.
In pl, all ASCII characters are essentially variables, but when the variable doesn't exist (yet), pl assumes that they are part of a string.
[Answer]
# [brainfuck](https://github.com/TryItOnline/brainfuck), ~~56~~ ~~55~~ 33 bytes
*1 byte saved thanks to Gravitron, and 22 bytes saved thanks to Jo King!*
```
--[>+<++++++],[[->.<]>+++.--.-<,]
```
[Try it online!](https://tio.run/##SypKzMxLK03O/v9fVzfaTttGGwxidaKjde30bGLtgBw9XV09XRud2P//PVJzcvJ1FMLzi3JSFAE "brainfuck ‚Äì Try It Online")
Output requires an interpreter that wraps on memory underflow and has EOI=0. TIO has such an interpreter.
## Explanation
`--[>+<++++++]` initializes the tape with a single `+`.
The input loop:
```
,[[->.<]>+++.--.-<,]
,                     take input
 [                ,]  while input is nonzero:
  [->.<]                  output `+` input times
        >+++.             output `.` (`+` + 3)
             --.          output `,` (`.` - 2)
                -<        restore `+` and move back to input
```
## Other solutions
Each line is its own solution.
```
+++[>+++++<-]>[>++++>+++<<-]>>-->,[[-<.>]<+++.---<.>>,]
--[>+<++++++],[[->.<]>+++.++++++++++++++++.-------------------<,]
++++++++++[>++++++>++++>++++<<<-]>>+++>++++++>,[[-<<.>>]<.<<.>>>,]
++++++++++[>++++++>++++>++++<<<-]>++>+++>++++++>,[[-<<.>>]<.<<.>>>,]
```
[Answer]
# [Mornington Crescent](https://github.com/padarom/esoterpret), 27640 bytes
```
Take Northern Line to Moorgate
Take Circle Line to Moorgate
Take Circle Line to Westminster
Take Circle Line to Hammersmith
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Barbican
Take Circle Line to Victoria
Take Circle Line to Victoria
Take Victoria Line to Seven Sisters
Take Victoria Line to Victoria
Take Circle Line to Victoria
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Bayswater
Take District Line to Barons Court
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Mile End
Take District Line to Cannon Street
Take Circle Line to Moorgate
Take Circle Line to Hammersmith
Take Circle Line to Cannon Street
Take Circle Line to Hammersmith
Take Circle Line to Cannon Street
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Mile End
Take District Line to Barking
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Bank
Take Circle Line to Bank
Take Northern Line to Charing Cross
Take Northern Line to Charing Cross
Take Bakerloo Line to Paddington
Take Circle Line to Royal Oak
Take Circle Line to Tower Hill
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Bank
Take Circle Line to Baker Street
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Baker Street
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Liverpool Street
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Bank
Take District Line to Gunnersbury
Take District Line to Upminster
Take District Line to East Ham
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Sloane Square
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take Circle Line to Cannon Street
Take District Line to Gunnersbury
Take District Line to Mile End
Take District Line to East Ham
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Plaistow
Take District Line to Mile End
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take District Line to Barking
Take District Line to Bank
Take District Line to Barking
Take District Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Wood Lane
Take Circle Line to Liverpool Street
Take Circle Line to Bank
Take Circle Line to Liverpool Street
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take District Line to Barking
Take District Line to Bank
Take District Line to Barking
Take District Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Dagenham East
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Victoria
Take Circle Line to Bank
Take Circle Line to Victoria
Take Circle Line to Hammersmith
Take District Line to Mile End
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Upminster
Take District Line to Mile End
Take Central Line to Bank
Take Circle Line to Victoria
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Wood Lane
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take District Line to Elm Park
Take District Line to Bank
Take Circle Line to Wood Lane
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Bank
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Bank
Take Central Line to Northolt
Take Central Line to Bank
Take Circle Line to Bank
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Barons Court
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Wimbledon
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Wood Lane
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Tower Hill
Take Circle Line to Bank
Take Circle Line to Wood Lane
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Bank
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Mile End
Take District Line to Upminster
Take District Line to Bank
Take Circle Line to Baker Street
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Bakerloo Line to Waterloo
Take Northern Line to Bank
Take Circle Line to Bank
Take Central Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Wood Lane
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Blackfriars
Take Circle Line to Bank
Take Circle Line to Wood Lane
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Paddington
Take Circle Line to Bank
Take Circle Line to Victoria
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Victoria
Take Circle Line to Wood Lane
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Wood Lane
Take Circle Line to Bank
Take Circle Line to Paddington
Take Circle Line to Victoria
Take Circle Line to Victoria
Take Victoria Line to Euston
Take Victoria Line to Victoria
Take Circle Line to Victoria
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Wood Lane
Take Circle Line to Paddington
Take Circle Line to Bank
Take Central Line to Northolt
Take Central Line to Bank
Take District Line to Southfields
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Baker Street
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Upminster
Take District Line to Ravenscourt Park
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Mile End
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take District Line to Upminster
Take District Line to Mile End
Take Central Line to Bank
Take Circle Line to Bank
Take Northern Line to Old Street
Take Northern Line to Bank
Take Circle Line to Bank
Take District Line to Gunnersbury
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take District Line to Mile End
Take Central Line to Theydon Bois
Take Central Line to Mile End
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Bank
Take Northern Line to Old Street
Take Northern Line to Bank
Take Circle Line to Bank
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Acton Town
Take Piccadilly Line to Cockfosters
Take Piccadilly Line to Acton Town
Take District Line to Acton Town
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Wood Lane
Take Circle Line to Paddington
Take Circle Line to Wood Lane
Take Circle Line to Bank
Take District Line to Elm Park
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bayswater
Take Circle Line to Paddington
Take Circle Line to Bayswater
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bayswater
Take Circle Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bayswater
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bayswater
Take District Line to Barking
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Barbican
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Barbican
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to East Ham
Take District Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take District Line to Elm Park
Take District Line to Bank
Take Central Line to Chancery Lane
Take Central Line to Bank
Take Circle Line to Bank
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Bank
Take District Line to Plaistow
Take District Line to Bank
Take Circle Line to Hammersmith
Take District Line to Mile End
Take Central Line to Bank
Take Circle Line to Bank
Take Circle Line to Farringdon
Take Circle Line to Bank
Take Circle Line to Bank
Take Central Line to Mile End
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Bank
Take Northern Line to Brent Cross
Take Northern Line to Bank
Take Circle Line to Bank
Take Central Line to Mile End
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take Circle Line to Notting Hill Gate
Take Circle Line to Notting Hill Gate
Take District Line to Upminster
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Farringdon
Take Circle Line to Bank
Take Circle Line to Tower Hill
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Farringdon
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Farringdon
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Southfields
Take District Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take District Line to Elm Park
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take District Line to Elm Park
Take District Line to Paddington
Take Circle Line to Blackfriars
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Royal Oak
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take District Line to Barons Court
Take District Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Blackfriars
Take Circle Line to Paddington
Take Circle Line to Blackfriars
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Royal Oak
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Farringdon
Take Circle Line to Paddington
Take Circle Line to Paddington
Take District Line to Southfields
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Embankment
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take District Line to East Ham
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take District Line to East Ham
Take District Line to Bank
Take District Line to Barking
Take District Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Barbican
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take District Line to West Ham
Take District Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take District Line to Barons Court
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Victoria
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Wood Lane
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Aldgate
Take Circle Line to Paddington
Take Circle Line to Aldgate
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take District Line to Barking
Take District Line to Paddington
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Bank
Take District Line to Barking
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Moorgate
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Central Line to Chancery Lane
Take Central Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take District Line to Barking
Take District Line to Paddington
Take Circle Line to Westminster
Take Circle Line to Paddington
Take District Line to Plaistow
Take District Line to Bank
Take Circle Line to Moorgate
Take Circle Line to Hammersmith
Take Circle Line to Bank
Take Northern Line to Charing Cross
Take Northern Line to Charing Cross
Take Northern Line to Bank
Take Circle Line to Bank
Take Circle Line to Paddington
Take Circle Line to Westminster
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take Circle Line to Aldgate
Take Circle Line to Temple
Take Circle Line to Hammersmith
Take District Line to Mile End
Take Central Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Bank
Take Circle Line to Westminster
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Mile End
Take Central Line to Bank
Take Circle Line to Bank
Take Northern Line to Charing Cross
Take Northern Line to Charing Cross
Take Northern Line to Bank
Take Circle Line to Tower Hill
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take Circle Line to Notting Hill Gate
Take Circle Line to Notting Hill Gate
Take District Line to Upminster
Take District Line to Tower Hill
Take Circle Line to Bank
Take Circle Line to Temple
Take Circle Line to Bank
Take Circle Line to Bayswater
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Bayswater
Take Circle Line to Tower Hill
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take Circle Line to Notting Hill Gate
Take Circle Line to Notting Hill Gate
Take District Line to Upminster
Take District Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Embankment
Take Circle Line to Hammersmith
Take Circle Line to Tower Hill
Take Circle Line to Bank
Take Circle Line to Embankment
Take Northern Line to Angel
Take Northern Line to Bank
Take Central Line to Marble Arch
Take Central Line to Bank
Take Circle Line to Bank
Take Circle Line to Westminster
Take District Line to Upminster
Take District Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Mile End
Take Central Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Mile End
Take Central Line to Bank
Take Circle Line to Bank
Take Northern Line to Charing Cross
Take Northern Line to Charing Cross
Take Northern Line to Bank
Take Circle Line to Tower Hill
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take Circle Line to Notting Hill Gate
Take Circle Line to Notting Hill Gate
Take District Line to Upminster
Take District Line to Embankment
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Piccadilly Line to Bounds Green
Take Piccadilly Line to Hammersmith
Take Circle Line to Embankment
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Cannon Street
Take Circle Line to Hammersmith
Take Circle Line to Cannon Street
Take District Line to Acton Town
Take District Line to Acton Town
Take Piccadilly Line to Bounds Green
Take Piccadilly Line to Holborn
Take Central Line to Holborn
Take Central Line to Bank
Take Circle Line to Hammersmith
Take District Line to West Ham
Take District Line to Bank
Take Circle Line to Aldgate
Take Circle Line to Aldgate
Take Metropolitan Line to Chalfont & Latimer
Take Metropolitan Line to King's Cross St. Pancras
Take Victoria Line to Seven Sisters
Take Victoria Line to Euston
Take Victoria Line to Euston
Take Northern Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Bank
Take Circle Line to Tower Hill
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Stepney Green
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Stepney Green
Take Hammersmith & City Line to Moorgate
Take Circle Line to Moorgate
Take Metropolitan Line to Chalfont & Latimer
Take Metropolitan Line to Moorgate
Take Circle Line to Moorgate
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Upminster
Take District Line to Bank
Take Circle Line to Tower Hill
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take Piccadilly Line to Russell Square
Take Piccadilly Line to Russell Square
Take Piccadilly Line to Acton Town
Take District Line to Acton Town
Take District Line to Bank
Take Circle Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Bank
Take District Line to East Ham
Take District Line to Bank
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take District Line to East Ham
Take District Line to Tower Hill
Take Circle Line to Bank
Take District Line to West Ham
Take District Line to Bank
Take Circle Line to Bank
Take Northern Line to Angel
Take Northern Line to Bank
Take Circle Line to Moorgate
Take Circle Line to Bank
Take Circle Line to Hammersmith
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Bank
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Barbican
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Moorgate
Take Circle Line to Bank
Take Northern Line to Morden
Take Northern Line to Bank
Take Circle Line to Bank
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Victoria
Take Victoria Line to Seven Sisters
Take Victoria Line to Victoria
Take Circle Line to Victoria
Take District Line to Mile End
Take District Line to Embankment
Take Northern Line to Kennington
Take Northern Line to Bank
Take Circle Line to Bank
Take Central Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Liverpool Street
Take Circle Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Aldgate
Take Metropolitan Line to Croxley
Take Metropolitan Line to Aldgate
Take Circle Line to Aldgate
Take Circle Line to Bank
Take Circle Line to Bank
Take District Line to Gunnersbury
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Hammersmith
Take District Line to Gunnersbury
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to West Brompton
Take District Line to Gunnersbury
Take District Line to Mile End
Take District Line to Acton Town
Take District Line to Mile End
Take District Line to Paddington
Take Circle Line to Paddington
Take Circle Line to Victoria
Take Victoria Line to Seven Sisters
Take Victoria Line to Victoria
Take Circle Line to Victoria
Take District Line to Mile End
Take District Line to Acton Town
Take District Line to Acton Town
Take Piccadilly Line to Hounslow Central
Take Piccadilly Line to Acton Town
Take District Line to Acton Town
Take District Line to Mile End
Take District Line to Gunnersbury
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Gunnersbury
Take District Line to Paddington
Take Circle Line to Bank
Take Circle Line to Bank
Take Northern Line to Mornington Crescent
```
[Try it online!](https://tio.run/##7V3dduMmEL7vU@iqvWrfIfamyTkb7@6J0@YaSyTmGIELOKmffouztde2JBA/A1LimxzHIDQMMx/zB665YIQ9K85@LwWWJWbq@/cHtMLFFy7UEgtW3BGGC8WLGefiGSn8y1vzlIiS4n6Nj1iqmjCpsGhtv0V1jYWsiVq2tl/RqnPsCWKrjgaxICVirY1/k1JxQVCPxv1/h@Y5fsGsmJPddGRHH4fx@86nwaRPmgKhhzr0@Gt9wuRG@wRt5SsytQvOZDHlG6E6utxsGNNELDZi29HDTqZ9jBnR875mVUfzFDHG9QoogbFyl0abtNmHDx8hYJUtzNGLuNIK7b06NiEKbY8hxp0av29oYNd0iYTmSjEVXMr@fSb6j6CcH/p8Q1X1Ay5bKbjnW0SLr6idvgf@ikVxSyjNql2WOVia4SXIIuDwBNhZaBBBLTBAih@Mm2ELDzDnnw2OMNafi25zvCMvWKw5p/2m4021x9rahPYaSbWbPpjWhI8ADU1zypH@NP9ngwSOB7H2zT2@qlpWE1TRkyw0Rfor/uo3v@iCFE@RHc0vt5V55Lwq7rSMxwAvn6dd6c/GVw@R@YSeMVui@k333q1xFcPEHL6LkBo/MiBodjvcL4phfCrY@c2/sOGG3OkUp5gpoX3KMMYCBpXeA1wM1bMy7/fRnKCm9Ulr3UmsXL0vT3oH5wYmIAgAOJzCFmew8hYM41Q5gk6QR5t7jwU3M3rE0@PiSuwJPJJ6QXHVOfy7RkVL8BaY2gsmfhDbA3TLCDaoA3IxAEHh6HtKI7/zuEuP6i86UkQ9iD7fOz8SRk4oKldP2gnZ58Vjk@sIPb7ci@RLuTEPhFgzY31faZupp/RZyAmp2bjeyMOwEYs1oBjoavvGDCP3n5OnD9FQ0znfqOUTwbSSY0qMDy7/BbLn2iZ1j14wk@XOxzHFDFIENIPDOGOwSAflMXoECho21Vdancisj9GVPaLnyKeHJd5qt7qYcCK9zMYRRD/Aqk3SSlJ2Pl5p@4Ptwg//M@obKUtUEUq3P0sSuDa7@VE9akuf82Gs70m73kE2ibf74BvoDo6lnBTixnw4WpQnRgk2KJvikpqrpCNIFGDdhB7l4lnjkC71/iOhxgRVjvV9sKISgKRnhs50iViJxfYYv5Okn4ZQazOAOpKYWUXXMr9opyA8JOas4U8kdsX/lb856mjBwwcD3A3oidBzMJ6RiM@HMfjcNnT8wpXanRzZZQeLmy7bo6NXYr/LV9B9859QG6zvPIZGT1BcdDy7fqpctIUiqAQWlFSZD5TlyfXbalryJjdsSwj7eND5wLCxLQAUGtC0g1GmxOh1vdAvrrXVAZp1dXXIhpYmThLA8WdS6qjLMIMIzQo8PCSv3605R8iwzwEk2/6VNegWUgORMQIfIAoBjwIfR4OqiBx@JWbUxTdexgGxnWXV0GTbe8Q4agLQ9Vcz2@VB1rf7BiGDLpGJfxeJVyzObQdw5HTEW5wecL2mOG0sOI59EvP2ENsCJLw8JEZlD7igW2KSl9CyKzW@QV6D@hoExyu7n8l9NlMbLTh@kdBox2XcwkS2x31X@Py1DXC7Ys@Y2oHvPKmGxEK/5UqUy1gZ0MbmE29tgHZaEHoybqVAbLps7BfYtKBff@lqqSyd8A2rZHEjMO4uUQ2EZ2/YB7nM0712tkcRbz82crrggrWrsrExAEAsQWgvPDtpm2El@JpTotAJgNAnzlTxa3GHFKn3st3a@bNWkt/kD7DRS/WHtvNYKZAMuMLXeGTsuLE/rI0Bt@ALQEZ4SHuu8Jrh7bFyjrKQqWUeRy/VmjYlautz4Xe4BvvfLg5xquMjaEHL9nK/kRJrS@P4Ck3/buFHTt41qARV1karPshYmOo6qd66F82CMfhAPf32GDiWKeQVOqyhkgIwoWhYshkXFWZJT5mOwSiAVvi0P6fhfNOyLUD3GTN2PLvBXwrT6ybfiPUc7baf4P9SvDX06O0dJrk4KLeSpLggMIXJ8rbTTgSv190J@eDD@XmPKg8bz2KEom75hknKX/e4le9Q@ce4rjoYXHwM2Nnhl780WO9/@es/ "Mornington Crescent ‚Äì Try It Online")
## Explanation
First, a quick refresher on Mornington Crescent:
* each station can either hold a string of arbitrary length or a bigint
* there's also an accumulator which also holds a string or a bigint
* all stations start with their own name as their value
* at the beginning, the accumulator contains your program's input
* each time you go to a station, the station's value and the accumulator are swapped
* some stations are special and override this behavior
* the line you use to get to a station doesn't matter
* you start at Mornington Crescent
* to end the program, you go to Mornington Crescent too
* at the end, the value of the accumulator is printed
Since printing strings is hard (see [Martin Ender's Mornington Crescent "Hello, World!" program](https://codegolf.stackexchange.com/a/57064/55934)), we will need a simple template that can be used to output generic strings. Since the length of the generated programs don't matter, I've settled on this:
```
Take Northern Line to Bank
Take Northern Line to Bank
Take District Line to Paddington
```
We'll need to generate each character separately and concatenate them, since the substring approach used by Martin is much harder to implement in the general case. Paddington is the station that performs string concatenation. When you arrive at Paddington, the following happens:
```
accumulator, paddington = paddington + accumulator, accumulator
```
This behavior is used to initialize Paddington to the empty string that's assumed to be the input.
```
Take District Line to Victoria
Take Victoria Line to Seven Sisters
Take Victoria Line to Euston
Take Victoria Line to Euston
Take Northern Line to Bank
```
Go to Seven Sisters, which sets the accumulator to 7, and store it in the Bank. The Bank is the only way to copy values - Hammersmith is a readonly copy of Bank's value.
```
Take District Line to Hammersmith
Take District Line to Cannon Street
Take District Line to Hammersmith
Take District Line to Cannon Street
Take District Line to Bank
```
Divide 7 by 7 to get 1, a divisor of all ASCII values we need to support.
```
Take District Line to Hammersmith
Take District Line to Upminster
```
For each character, start by copying the 1 to Upminster.
```
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Upminster
```
Add more ones as necessary.
```
Take District Line to Hammersmith
Take District Line to Upminster
Take District Line to Bank
Take District Line to Bank
Take Northern Line to Charing Cross
Take Northern Line to Charing Cross
Take Bakerloo Line to Paddington
Take Bakerloo Line to Paddington
Take Bakerloo Line to Charing Cross
Take Northern Line to Embankment
```
Finish up by going to Upminster only once, to keep the new value in the accumulator instead of storing it again. Take it to Charing Cross to turn the ASCII value into a character and append it to the string. The last two lines are there because I've misread the specification, so I'll stop here and golf my program down first.
[Answer]
# [Jelly](https://github.com/DennisMitchell/jelly), 1 byte
```
·πæ
```
Woo builtins!
The builtin `·πæ` unevals the input.
[Try it online!](https://tio.run/##y0rNyan8///hzn3///9XCkktLsnMSzc0MlYCAA "Jelly ‚Äì Try It Online")
A more interesting one:
```
‚Åæ‚Äú‚Äùj
```
Joins the string "‚Äú‚Äù" by the input.
[Try it online!](https://tio.run/##y0rNyan8//9R475HDXMeNczN@v//v1JIanFJZl66oZGxEgA "Jelly ‚Äì Try It Online")
[Answer]
# Charcoal, 1 byte
```
Œ∏
```
By default, a string of ASCII characters  .. `~` simply prints itself, so it just remains to print the input.
[Answer]
# [C (gcc)](https://gcc.gnu.org/), ~~89~~ ~~87~~ ~~58~~ 56 bytes
*Saved two bytes thanks to Jakob!*
```
main(a,c)char**c;{printf("main(){puts(\"%s\");}",c[1]);}
```
[Try it online!](https://tio.run/##S9ZNT07@/z83MTNPI1EnWTM5I7FISyvZurqgKDOvJE1DCSyjWV1QWlKsEaOkWhyjpGldq6STHG0YC2T8//@/JLW4JDMv3dDIGAA "C (gcc) ‚Äì Try It Online")
[Answer]
# [Japt](https://github.com/ETHproductions/japt), 2 bytes
```
iQ
```
[Try it online!](https://tio.run/##y0osKPn/PzPw/3@lzLyC0pLikqLMvHQlAA "Japt ‚Äì Try It Online")
`i` is a function that inserts a specified string at a specified index into the input. `Q` is a variable that defaults to a quotation mark `"`, and since there's no index given, this defaults to `0`. The end result is a quotation mark inserted at the beginning of the string, which Japt auto-finishes when running.
This works on strings containing anything except `"`, `{`, or `\`, though of course the string is guaranteed to consist of alphanumeric chars so this doesn't matter.
[Answer]
# [Python 2](https://docs.python.org/2/), 22 bytes
```
print'print%r'%input()
```
[Try it online!](https://tio.run/##K6gsycjPM/r/v6AoM69EHUyqFqmrZuYVlJZoaP7/r16SWlySmZduaGSsDgA "Python 2 ‚Äì Try It Online")
[Answer]
# MATLAB / [Octave](https://www.gnu.org/software/octave/), 15 bytes
```
@(t)['disp ',t]
```
[Try it online!](https://tio.run/##y08uSSxL/Z9mq6en999Bo0QzWj0ls7hAQV2nJPZ/moZ6SWpxSWZeuqGRsbomF1gGIfIfAA "Octave ‚Äì Try It Online")
I completely overlooked the fact that the program only needs to handle alphanumeric characters, or, importantly, does **not** need to handle space characters. This means we can use the 'command' syntax, which uses significantly less bytes.
### MATLAB, 27 bytes
For completeness, here's a version that can handle arbitrary input:
```
@(t)['disp(',mat2str(t),41]
```
Defines an anonymous function taking the string `t`, and converts it to the program. Curiously, this does not work in Octave, which seems to have different ideas of what `mat2str` should do.
[Answer]
# PowerShell, 9 Bytes
```
"'$args'"
```
single or double quotes in powershell can be used to contain strings, but only double-quotes allow variable expansion.
with an input of `foo` this will output `'foo'` which is a valid powershell program which outputs `foo`
[Answer]
# [Befunge-98 (FBBI)](https://github.com/catseye/FBBI), ~~21~~ ~~16~~ 12 bytes
-5 bytes thanks to [NieDzejkob](https://codegolf.stackexchange.com/users/55934/niedzejkob)  
-4 bytes thanks to [Jo King](https://codegolf.stackexchange.com/users/76162/jo-king)
```
#,~'',,',,'@
```
[Try it online!](https://tio.run/##S0pNK81LT9W1tPj/X1mnTl1dRweEHP7/L0ktLsnMSzc0MgYA "Befunge-98 (FBBI) ‚Äì Try It Online")
Outputs `'t,'e,'s,'t,@` for an input of `test`
### How?
Initially the pointer moves East:
```
#,           # skips the next instruction
  ~          push a byte of input
   '',       push ' and print it
      ,      print the byte of input
       ',,   push , and print it 
          '@ push @ to the stack
```
If there is no more input left, `~` reverses the direction of the pointer:
```
 ,           print @
#            skip nothing
           @ terminate
```
[Answer]
# [Emojicode](http://www.emojicode.org/), 88 bytes
```
üêñüòç‚û°Ô∏èüî°üçáüçéüç™üî§üèÅüçáüòÄ‚ùåüî§üî§üêïüî§‚ùåüî§üçâüî§üç™üçâ
```
[Try it online!](https://tio.run/##S83Nz8pMzk9J/f9h/oRuhQ/zpywEEr3tIO60D/Nn9D6at/D9jn6QOEgYiPuAeBWQv@TD/P5GiNiMhkdzeyBCIDxhKoiGC/V2QulVIPZ/EMEF08ulANINsgdk9ZLEvMrgkqLMvHQQhwusHAA "Emojicode ‚Äì Try It Online")
**Input:**
```
anyString
```
**Output:**
```
üèÅüçáüòÄüî§anyStringüî§üçâ
```
**Script Output:**
```
anyString
```
[Answer]
# [QBIC](https://drive.google.com/drive/folders/0B0R1Jgqp8Gg4cVJCZkRkdEthZDQ), 7 bytes
```
?@?@`+;
```
## Explanation
```
?           PRINT on the screen
 @  `       a literal
  ?@         question mark and at
     +;     and append the input
```
## Sample run
```
Command line: lala
?@lala
```
The output is a string literal containing the input, preceded with a `PRINT` command.
[Answer]
# [Batch](https://en.wikipedia.org/wiki/Batch_file) 11 bytes
I'm sure there's away to get it smaller, but this is pretty small.
```
set/p=echo 
```
### The breakdown:
```
set             ::Define new variable
   /p           ::Create prompt
     =          ::Define a variable in prompt
      echo      ::Prompt begins with 'echo '
```
## In English:
The user is asked for input with a leading phrase `echo`. Then the user may type in whatever, and the program terminates (e.g; `echo hello world!`). This leaves us with a program that when ran, will output `hello world!`.
*Yes, the whitespace is supposed to be there*
[Answer]
# V, 2 bytes
```
ii
```
In Vim, `i` changes to insert mode and allows inserting text. In this case, it just inserts the `i` in front of the input text (to create the second program). V is Vim compatible, but adds an implicit `<esc>` to the end of the program, so I don't need to worry about it here.
[Answer]
# [Cubically](https://github.com/aaronryank/cubically), 87 bytes
```
U3D1R3L1F3B1U1D3~:7+1(-1@3(-1%1)6:1+3111@6%1-31111+004@6:1+11111%6:1+45@6:1-1%6~:7+1)6 
```
[Try it online!](https://tio.run/##Sy5NykxOzMmp/P8/1NjFMMjYx9DN2Mkw1NDFuM7KXNtQQ9fQwRhIqBpqmlkZahsbGho6mKka6oIYhtoGBiYOIGEQx1AVxDIxBQkA1ZuBtWuaKfz/75Gak5OvoxCeX5SToggA "Cubically ‚Äì Try It Online")
A port of my answer [here](https://codegolf.stackexchange.com/a/137695/71434). There already existed a challenge to take input and output Cubically code that produced that input, and I had an answer in Cubically so... profit?
[Answer]
# D, ~~92~~ 89 bytes
```
void main(){import std.stdio;write(`void main(){import std.stdio;"`~readln~`".write;}`);}
```
[Try it online!](https://tio.run/##S/n/vyw/M0UhNzEzT0OzOjO3IL@oRKG4JEUPiDPzrcuLMktSNRLwqlFKqCtKTUzJyatLUNIDa7CuTdC0rv3/Pzgk1M0NAA)
[Answer]
# SmileBASIC, 21 bytes
Maybe this is cheating...
```
LINPUT"?"+CHR$(34);S$
```
Asks for input with the prompt `?"`. (? is short for PRINT, and closing quotes are not required). So the "output" program is `?"<text>`
[Answer]
# [Python 2](https://docs.python.org/2/), 17 bytes
```
'print%r'.__mod__
```
[Try it online!](https://tio.run/##K6gsycjPM/qfZhvzX72gKDOvRLVIXS8@Pjc/JT7@P1hAIU1DvSS1uERdkwvM50qtSE1GCP4HAA "Python 2 ‚Äì Try It Online")
[Answer]
# [SOGL V0.12](https://github.com/dzaima/SOGL), 2 [bytes](https://github.com/dzaima/SOGL/blob/master/chartable.md)
```
$+
```
[Try it Here!](https://dzaima.github.io/SOGLOnline/?code=JTJDJTI0Kw__,inputs=aGVsbG8_) (expects input on stack so `,` is added for ease-of-use)
`$` pushes `‚Äù`, `+` joins that after the input on the stack.
[Answer]
# [Perl¬†6](https://perl6.org), 19 bytes
```
say "say "~get.perl
```
[Try it](https://tio.run/##K0gtyjH7/784sVJBCUzUpaeW6BUARf//d8vPBwA "Perl 6 ‚Äì Try It Online")
This should work for any Unicode input in NFC
[Answer]
# [8th](http://8th-dev.com/), ~~34~~ 37 bytes
**Code**
```
: f >s "\"" tuck s:+ s:+ " ." s:+ . ;
```
**Example**
```
ok> "Print 42" f
"Print 42" .
ok> "Print 42" .
Print 42
```
[Answer]
# [PHP](https://php.net/), 12 bytes
```
<?=$argv[1];
```
[Try it online!](https://tio.run/##K8go@P/fxt5WJbEovSzaMNb6////JanFJZl56YZGxgA "PHP ‚Äì Try It Online")
This is to be run from the command line with the input as the parameter argument. And yes, it simply outputs the input string‚Äîbut that is valid PHP: anything outside the `<?php` `?>` delimiters is output unprocessed.
Here is the script produced by the 'testing123' input in action as a demonstration: [Try it online!](https://tio.run/##K8go@P@/JLW4JDMv3dDI@P9/AA "PHP ‚Äì Try It Online")
[Answer]
# [MATL](https://github.com/lmendo/MATL), 2 bytes
```
&D
```
[Try it online!](https://tio.run/##y00syfn/X83l/3/1ktTiksy8dEMjY3UA "MATL ‚Äì Try It Online")
Simply wraps the string in quotes using `&D`, which is MATL's equivalent to MATLAB's `mat2str`, a function specifically made to make something that, when `eval`'d, will give the original matrix (or in this case, string).
The resulting 'program' is just the input string wrapped in quotes, which is thus pushed on the stack, and implicitly displayed.
[Answer]
# [eacal](https://github.com/ConorOBrien-Foxx/eacal), 38 bytes
```
strap string put string 
put strap arg
```
[Try it online!](https://tio.run/##S01MTsz5/7@4pCixQAFIZualKxSUlsCYXFA2UDKxKP3///8lqcUlQAlDI2MA "eacal ‚Äì Try It Online")
Simply appends the string `put string` to the memory string, then appends the argument, which is printed.
[Answer]
## Batch, 14 bytes
```
@echo @echo(%*
```
Works for special characters too if they are quoted using `"`s rather than `^`.
[Answer]
# [Ly](https://esolangs.org/wiki/Ly), 14 bytes
```
"\""&i"\"&o"&o
```
[Try it online!](https://tio.run/##y6n8/18pRklJLRNIquUD0f//JanFJQA)
### Explanation
```
"\""&i"\"&o"&o
"\""           # push `"`
    &i         # take input
      "\"&o"   # push `"&o`
            &o # output stack
               # test -> "test"&o
               # "test"&o = push "test" and output stack
```
[Answer]
# JavaScript ES6, 25 bytes (outputs code to "standard output")
```
s=>alert(`alert('${s}')`)
```
# JavaScript ES6, 23 bytes (returns code, that outputs to "standard output")
```
s=>`alert('${s}')`
```
# JavaScript ES6, 14 bytes (returns a function, that returns the result)
```
s=>`_=>"${s}"`
```
[Answer]
# [Brain-Flak](https://github.com/DJMcMayhem/Brain-Flak), ~~92~~ 68 bytes
-22 bytes thanks to [Wheat Wizard](https://codegolf.stackexchange.com/users/56656/wheat-wizard)
Includes +2 for `-cr`
```
{<>(((((()()()()()){}){}){})())<>{({}[()])<>((({}[()])()))<>}{}}<>
```
[Try it online!](https://tio.run/##SypKzMzTTctJzP7/v9rGTgMMNGFQs7oWioBsG7tqjeraaA3NWE2wQigbKAPk11bX1trY/f@fmJT8Xze5CAA "Brain-Flak ‚Äì Try It Online\" It Online")
```
# For every character
{
   # Put ")(" on the off stack
   <>(((((()()()()()){}){}){})())<>
   # for 0 to the ASCII value of this character
   {({}[()])
      # Replace the ")" with "(" and add "))"
      <>((({}[()])()))<>
   # End for
   }{}
# end for and switch to the off stack for printing (in reverse order because of -r)
}<>
```
[Answer]
# [Pyth](https://github.com/isaacg1/pyth), ~~2~~ 1 byte
```
z
```
[Try it online!](https://tio.run/##K6gsyfj/v@r/f6XEnPyMRCUA "Pyth ‚Äì Try It Online")
Just outputs the input. Requires strings to be in quotes.
*-1 byte thanks to KarlKastor*
]