Validation for 4 digit pin

A first idea here. Not sure if it catches all edge cases.

a!localVariables(
  local!pins: {"7369", "1234", "4321", "0000", "1111", "4444", "2222", "3333"},
  a!forEach(
    items: local!pins,
    expression: and(
      fv!item <> concat(tointeger(left(fv!item, 1)) + enumerate(4)), /* positive sequence */
      fv!item <> concat(tointeger(left(fv!item, 1)) + enumerate(4) * -1), /* negative sequence */
      fv!item <> rept(mid(fv!item, 1, 1), 4), /* 4 times the first character */
      fv!item <> rept(mid(fv!item, 2, 1), 4), /* 4 times the second character */
      fv!item <> rept(mid(fv!item, 3, 1), 4), /* 4 times the third character */
      fv!item <> rept(mid(fv!item, 4, 1), 4) /* 4 times the fourth character */
    )
  )
)

Hi Druva,

Please try the below code. Here rule input (ri!pin) is of type text

if(
  and(
    len(ri!pin)=4,
    len(tostring(tointeger(ri!pin)))=len(ri!pin)
  ),
  a!localVariables(
    local!numbersUsed:{
      int(charat(ri!pin,1)),
      int(charat(ri!pin,2)),
      int(charat(ri!pin,3)),
      int(charat(ri!pin,4))
    },
    if(
      length(union(local!numbersUsed,local!numbersUsed))<>length(local!numbersUsed),
      "numbers cannot be repeated in pin",
      if(
        and(
          local!numbersUsed[1]+1=local!numbersUsed[2],
          local!numbersUsed[2]+1=local!numbersUsed[3],
          local!numbersUsed[3]+1=local!numbersUsed[4],
        ),
        "cannot be sequentail numbers",
        "no error"
      )
    )
  ),
  "pin should be 4 characters and should contain only numbers"
)

a!localVariables(
local!a:regexmatch(
pattern:"^(?!.*?(?:012|123|234|345|456|567|678|789|987|876|765|654|543|432|321|210|(\d)\1\1))\d{4}$",
searchString:9989,
regexFlags:"gms"
),
local!a
)

Hi , can you check the above code by placing in expression rule working fine for me .
if you don't find regexmatch() in your rule , then add "Regular expression functions" plugin

Hi, 
Here is a solution which covers all edge cases. (Some humble bragging)
The expression rule 'isPinValid' provides an array as a result. 
The first item in the result is a Boolean indicating if the Pin is valid, the second item in the result is the validation message

a!localVariables(
  /* Checks if the pin is compliant to the rules: has 4 digits, no sequences (ascending or descending) and not the same 4 digits */
  /* Get the digits of the pin - ri!pin is in text format */
  local!allDigits: tostring(ri!pin), 
  local!count: len(local!allDigits),
  local!digits: a!forEach(items: enumerate(local!count),expression: tointeger(local!allDigits[fv!index])),
  /* Prep for the sequence test, calculating the difference between the digits - ldrop is for the edge case if the pin starts with a 1 */
  local!seq:ldrop({0,local!digits} - {local!digits,0},1),
  /* Same digits? */
  local!sd: if(1=length(union(local!digits,local!digits)),true,false),
  /* Check if we have a sequence of numbers e. g. 2345 or 8765 */
  local!seq1: if(3<=length(wherecontains(-1,local!seq)),true,false),
  local!seq2: if(3<=length(wherecontains(1,local!seq)),true,false),
  /* Is the pin valid (true), or is one of the rules violated? (false) */
  local!check: not(or(4<>local!count,local!sd,local!seq1,local!seq2)),
   { 
    local!check,
    /* Providing the confirmation and/or error message  */
    a!match(value:true,
    whenTrue: count(local!digits)<>length(local!digits),
    then: "Pin can only contain Digits",
    whenTrue: local!check,
    then: "Pin is valid",
    whentrue:4<>local!count,
    then: "Pin has not 4 digits",
    whentrue: local!sd,
    then: "Pin can't have the same 4 digits",
    whenTrue: or(local!seq1,local!seq2),
    then: "Pin can't have digits in " & if(local!seq1,"a","de") & "cending sequence",
    default: "Not a valid pin"
    )
  }
)