Replace pattern containing more than one arithmetic expressions

Question

My problem is to search all expressions in a file containing: (Scenario in converting from fortran to C)

Arr1 = Arr2[4:10]

and replace with

for(i = 0 ;i < 6; i++) Arr1[ i ] = Arr2[ i+3 ]

//comment i + 3 because i + "4-1". i< 6 because 6 = "10 - 4"

I tried this in vi but this is not working:

:%s/(\<\w+>)\s+=\s+(\<\w+>)[([0-9]):([0-9])]/\='for(i=0;i<'.(submatch(4) - submatch(3)).' ;i++) \1[i] = \2[i+'.(submatc h(3) - 1).']'/gc

Kindly help. The names of arrays used in file are not same. The array indices are not same for all arrays too. Hope the question is clear. I tried using \= and submatch() as in another answer but, that is not allowing separate strings containing arithmetic evaluation expressions to be concatenated. I am missing something.

Answer 1

I'm not sure this is what you want, but you could try this substitution command:

%s/\v(<\w+>)\s+\=\s+(<\w+>)\[(\d+):(\d+)\]/\='for(i=0;i<'.(submatch(4) - submatch(3)).' ;i++) '.submatch(1).'[i] = '.submatch(2).'[i+'.(submatch(3) - 1).']'/gc
      |              |        |     |         |            |                                    |            |   |   |            |                          |
      |              |        |     |         |            |                                    |            |   |   |            |                          +-- flags
      |              |        |     |         |            |                                    |            |   |   |            +-- index of the second array item
      |              |        |     |         |            |                                    |            |   |   +-- name of the second array
      |              |        |     |         |            |                                    |            |   +-- assignment 1st array item = 2nd array item
      |              |        |     |         |            |                                    |            +-- index of the first array item
      |              |        |     |         |            |                                    +-- name of the first array
      |              |        |     |         |            +-- upper limit of the for loop
      |              |        |     |         +-- beginning of the replacement (for loop)
      |              |        |     +-- capture the number 10 inside `Arr2[4:10]`
      |              |        +-- capture the number 4 inside `Arr2[4:10]`
      |              +-- capture the name of the 2nd array
      +-- capture the name of the 1st array