Environments, Tables, And Troff Macros - fortran_continuation_line (7)

NAME

fortran_continuation_line(7f) - [FORTRAN] Fortran Continuation Lines

DESCRIPTION

If a statement is too long to fit on a line, it can be continued with the following methods: If a line is ended with an ampersand, &, it will be continued on the next line. Continuation is normally to the first character of the next non-comment line.
   A = 174.5 * Year   &
       + Count / 100
The above is equivalent to the following
   A = 174.5 * Year  + Count / 100
Note that & is not part of the statement.
   A = 174.5 * Year   &
   !  this is a comment line
       + Count / 100
The above is equivalent to the following, since the comment is ignored by the compiler:
   A = 174.5 * Year  + Count / 100
If the first non-blank character of the continuation line is &, continuation is to the first character after the &:
   A = 174.5 + ThisIsALong&
        &VariableName * 123.45
is equivalent to
   A = 174.5 + ThisIsALongVariableName * 123.45
In this case, there should be no spaces between the last character and the & on the first line. For example,
   A = 174.5 + ThisIsALong   &
        &VariableName * 123.45
is equivalent to
   A = 174.5 + ThisIsALong   VariableName * 123.45
Note that there are spaces between ThisIsALong and VariableName. In this way, a token (name and number) can be split over two lines. However, this is not recommended

SPECIFICALLY

3.3.2.4 Free form statement continuation

1. The character "&" is used to indicate that the current statement is continued on the next line that is not a comment line. Comment lines cannot be continued; an "&" in a comment has no effect. Comments may occur within a continued statement. When used for continuation, the "&" is not part of the statement. No line shall contain a single "&" as the only nonblank character or as the only nonblank character before an "!" that initiates a comment.

2. If a noncharacter context is to be continued, an "&" shall be the last nonblank character on the line, or the last nonblank character before an "!". There shall be a later line that is not a comment; the statement is continued on the next such line. If the first nonblank character on that line is an "&", the statement continues at the next character position following that "&"; otherwise, it continues with the first character position of that line.

3. If a lexical token is split across the end of a line, the first nonblank character on the first following noncomment line shall be an "&" immediately followed by the successive characters of the split token.

4. If a character context is to be continued, an "&" shall be the last nonblank character on the line and shall not be followed by commentary. There shall be a later line that is not a comment; an "&" shall be the first nonblank character on the next such line and the statement continues with the next character following that "&".

So this is OK:
   POINT=[&   ! define a Point <X,Y,Z>
   & 10, &    ! the X component
   & 20, &    ! the Y component
   & 30  ]    ! the Z component
because you can have comments after the ampersand when it is not a string. But this is not OK:
   STRING=[’&   ! create a sentence
   & This&      ! first word
   & is&        ! second word
   & sentence&  ! third word
   & a’]        ! forth word (a comment here is OK)
Because when continuing a string you cannot have a comment after the ampersand. This is OK:
   STRING=[’&
   ! create a sentence
   & This&
   ! first word
   & is&
   ! second word
   & sentence&
   ! third word
   & a’]        ! forth word (a comment here is OK)
Long strings:
   Subroutine LongString()

   Character (len=200) :: string1, String2
   string1 = "A very long string that won’t fit on a single &
              &line can be made through proper continuation."

   string2 = "A very long string that won’t fit on a single " // &
             "line can be made through proper continuation."
   if (string1 == string2) then
     print *, "string1 and 2 are identical!"
     print *, "string1 & 2=",string1
   else
     print *, "string1 and 2 don’t match!"
   endif

   End Subroutine LongString

Nemo Release 3.1

fortran_continuation_line (7)

February 23, 2025

Generated by manServer 1.08 from 01eb3a6c-1223-4221-8ed0-6bb6b7925e49 using man macros.

1.	The character "&" is used to indicate that the current statement is continued on the next line that is not a comment line. Comment lines cannot be continued; an "&" in a comment has no effect. Comments may occur within a continued statement. When used for continuation, the "&" is not part of the statement. No line shall contain a single "&" as the only nonblank character or as the only nonblank character before an "!" that initiates a comment.
2.	If a noncharacter context is to be continued, an "&" shall be the last nonblank character on the line, or the last nonblank character before an "!". There shall be a later line that is not a comment; the statement is continued on the next such line. If the first nonblank character on that line is an "&", the statement continues at the next character position following that "&"; otherwise, it continues with the first character position of that line.
3.	If a lexical token is split across the end of a line, the first nonblank character on the first following noncomment line shall be an "&" immediately followed by the successive characters of the split token.
4.	If a character context is to be continued, an "&" shall be the last nonblank character on the line and shall not be followed by commentary. There shall be a later line that is not a comment; an "&" shall be the first nonblank character on the next such line and the statement continues with the next character following that "&".