---

Manual Reference Pages  - trim_quoted (3m_strings)

---

NAME

trim_quoted(3f) - [M_strings:WHITESPACE] converts regions of whitespace characters to a specified string (or nothing) (LICENSE:PD)

CONTENTS

Synopsis
Description
Options
Returns
Examples
References
Author
License

SYNOPSIS

function trim_quoted(STR,K) result (OUTSTR)

    character(len=*),intent(in)          :: STR
    character(len=*),intent(in),optional :: REP
    character(len=len(str))              :: OUTSTR

DESCRIPTION

Whitespace is trimmed from both ends of the input string.

Text found between single and/or double quotes is not altered. A single quote is only considered a delimiter if preceded by a space or as the first non-blank character to allow for the use of a single quote in contractions.

Otherwise, trim_quoted(3) changes ranges of whitespace of various length found between words to a specified replacment string.

This would be similar to the sed(1) Basic Regular Expression

       sed -i -e ’s/  */REP/g’

if no quoted regions were present.

OPTIONS

STR	input string whose whitespace regions are to be replaced
REP	string used to replace each region of whitespace. Defaults to a single blank.

RETURNS

OUTSTR	Ouput string with all internal whitespace sections replaced by the replacement string removed

EXAMPLES

Sample Program:

   program demo_trim_quoted
   use M_strings, only: trim_quoted
   implicit none
   character(len=*),parameter   :: bracket=’(*("[",g0,"]":,","))’
   character(len=*),parameter   :: uno=’(/,*(g0:,/))’
   character(len=:),allocatable :: a,b

   a = ’Esto es    una   prueba a ver como sale y determinar si  &
   & realmente   funciona bien la ruutina para eliminar blancos  &
   & "intermedios  de  una    hola      cadena  de  caracteres"  &
   &  y ver ademas si "(respetamos     las       comillas) "     &
   &   realmente respeta las cadenas encerradas entre comillas.  &
   &vamos a ver como sale este negocio. que mas puedo decir.     &
   &probemos y veamos que pasa’

   print uno, ’Original tal y como se escribio (sin trim_quoted)’,a
   print uno, ’reducir espacios a uno 1’, trim_quoted (a, ’ ’)
   print uno, ’reducir espacios a dos 2’, trim_quoted (a, ’  ’)
   print uno, ’reducir espacios a cero 0’, trim_quoted (a, ’’)

   a = "This is a    test to see how it turns out and to determine if the&
   & routine to eliminate ’intermediate    spaces   from a text string’  &
   & really works well, and also to see if ’(we respect       quotation  &
   & marks)’   really respects strings enclosed   in quotes. Let’s see   &
   & how this business turns out. What else can I say. Let’s test and see&
   & what       happens."

   print uno, "Original exactly as it was written (without trim_quoted)",a
   print uno, ’reduce spaces to one 1’, trim_quoted (a, ’ ’)
   print uno, ’reduce spaces to two 2’, trim_quoted (a, ’  ’)
   print uno, ’reduce spaces to zero 0’, trim_quoted (a, ’’)

   b = trim_quoted(a, ’’)
   print *, b

   write(*,bracket)trim_quoted(’this and    that’,’’)

   write(*,bracket)trim_quoted(’ a b  c  ’),’a b c’
   write(*,bracket)trim_quoted(’a’,’xxxxx’),’a’
   write(*,bracket)trim_quoted(’’,’xxxxx’),’’
   write(*,bracket)trim_quoted(’ a b   c " don’’t  touch " d   e’,’:’),&
   & ’a:b:c:" don’’t  touch ":d:e’
   write(*,bracket)trim_quoted(’  a ’,’xxxxx’),’a’
   write(*,bracket)trim_quoted("  a ’  quoted   text ’",’--’),&
   & "a--’  quoted  text ’"
   write(*,bracket)trim_quoted("  a ’  quoted   text ’ abcd efg",’--’),&
   & "a--’  quoted  text ’--abcd--efg"
   end program demo_trim_quoted

   Expected output

    > Original tal y como se escribio (sin trim_quoted)
    > Esto es    una   prueba a ver como sale y determinar si
    > realmente   funciona bien la ruutina para eliminar blanco
    > s   "intermedios  de  una    hola      cadena  de  caract
    > eres"    y ver ademas si "(respetamos     las       comil
    > las) "        realmente respeta las cadenas encerradas en
    > tre comillas.  vamos a ver como sale este negocio. que ma
    > s puedo decir.     probemos y veamos que pasa
    >
    > reducir espacios a uno 1
    > Esto es una prueba a ver como sale y determinar si realme
    > nte funciona bien la ruutina para eliminar blancos "inter
    > medios  de  una    hola      cadena  de  caracteres" y ve
    > r ademas si "(respetamos     las       comillas) " realme
    > nte respeta las cadenas encerradas entre comillas. vamos
    > a ver como sale este negocio. que mas puedo decir. probem
    > os y veamos que pasa
    >
    > reducir espacios a dos 2
    > Esto  es  una  prueba  a  ver  como  sale  y  determinar
    > si  realmente  funciona  bien  la  ruutina  para  elimin
    > ar  blancos  "intermedios  de  una    hola      cadena
    > de  caracteres"  y  ver  ademas  si  "(respetamos     la
    > s       comillas) "  realmente  respeta  las  cadenas  e
    > ncerradas  entre  comillas.  vamos  a  ver  como  sale
    > este  negocio.  que  mas  puedo  decir.  probemos  y  ve
    > amos  que  pasa
    >
    > reducir espacios a cero 0
    > Estoesunapruebaavercomosaleydeterminarsirealmentefunciona
    > bienlaruutinaparaeliminarblancos"intermedios  de  una
    > hola      cadena  de  caracteres"yverademassi"(respetamos
    > las       comillas) "realmenterespetalascadenasencerradas
    > entrecomillas.vamosavercomosaleestenegocio.quemaspuedodec
    > ir.probemosyveamosquepasa
    >
    > Original tal y como se escribio (sin trim_quoted)
    > This is a    test to see how it turns out and to determin
    > e if the routine to eliminate ’intermediate    spaces   f
    > rom a text string’   really works well, and also to see i
    > f ’(we respect       quotation   marks)’   really respect
    > s strings enclosed   in quotes. Let’s see    how this bus
    > iness turns out. What else can I say. Let’s test and see
    > what happens.
    >
    > reduce spaces to one 1
    > This is a test to see how it turns out and to determine i
    > f the routine to eliminate ’intermediate    spaces   from
    > a text string’ really works well, and also to see if ’(we
    > respect       quotation   marks)’ really respects strings
    > enclosed in quotes. Let’s see how this business turns out
    > . What else can I say. Let’s test and see what happens.
    >
    > reduce spaces to two 2
    > This  is  a  test  to  see  how  it  turns  out  and  to
    >  determine  if  the  routine  to  eliminate  ’intermedia
    > te    spaces   from a text string’  really  works  well,
    >   and  also  to  see  if  ’(we respect       quotation
    >  marks)’  really  respects  strings  enclosed  in  quote
    > s.  Let’s  see  how  this  business  turns  out.  What
    > else  can  I  say.  Let’s  test  and  see  what  happens.
    >
    > reduce spaces to zero 0
    > Thisisatesttoseehowitturnsoutandtodetermineiftheroutineto
    > eliminate’intermediate    spaces   from a text string’rea
    > llyworkswell,andalsotoseeif’(we respect       quotation
    >  marks)’reallyrespectsstringsenclosedinquotes.Let’sseehow
    > thisbusinessturnsout.WhatelsecanIsay.Let’stestandseewhath
    > appens.
    > Thisisatesttoseehowitturnsoutandtodetermineiftheroutineto
    > eliminate’intermediate    spaces   from a text string’rea
    > llyworkswell,andalsotoseeif’(we respect       quotation
    >  marks)’reallyrespectsstringsenclosedinquotes.Let’sseehow
    > thisbusinessturnsout.WhatelsecanIsay.Let’stestandseewhath
    > appens.
    > [thisandthat]
    > [a b c],[a b c]
    > [a],[a]
    > [],[]
    > [a:b:c:" don’t  touch ":d:e],[a:b:c:" don’t  touch ":d:e]
    > [a],[a]
    > [a--’  quoted   text ’],[a--’  quoted  text ’]
    > [a--’  quoted   text ’--abcd--efg],[a--’  quoted  text ’--abcd--efg]

REFERENCES

Based on a contribution by Francisco Iglesias:

https://fortran-lang.discourse.group/t/ sharing-a-classic-fortran-77 -utility-a-robust-string-trimming-function -with-quotes-protection-itrim/1097

AUTHOR

o	Francisco Iglesias (October-2024)
o	modified by John S. Urban for inclusion in M_strings(3) (June 2026), changed to use a replacement string instead of a specified number of blanks.

LICENSE

Public Domain

---