#700 Add support for quotes to 'word' and 'words' functions

[Christoph Bersch]

Hi,

the attached patch add support for quotes to the word and words functions. That means, that one can use something like

str = "one 'second word' three"
print word(str, 2)

which prints second word.

See the attached demo file for more test cases, including handling of wrapped quotes and more special cases.

[Christoph Bersch]

Some more explanations:

• The code doesn't recognize escaped quote characters, but e.g. single quotes can be nested inside of double quotested inside of double quotes:

  s = "A \"'quoted string'\""
  do for [i=1:words(s)]{ print word(s,i)}
  

  The output is:

  A
  'quoted string'
  

• Another thing is, that starting quotes are recognized only when they appear at the string start, or after a white space.

  s = 'A str"ing'
  do for [i=1:words(s)]{ print word(s,i)}
  

  The output is:

  A
  str"ing
  

  As closing quote, however, the next matching character is selected:

  s = 'A "str"ing'
  do for [i=1:words(s)]{ print word(s,i)}
  

  The output is:

  A
  str
  ing
  

So, the code should handle many practical situations.

[Ethan Merritt]

I am not so sure this is a good idea.
Doesn't it conflict with processing apostrophes in a normal text string?
And doesn't it conflict with existing processing of text in data files?

E.g.

$DATA << EOD
#Passengers per car
Day  Mine Joanna's Ricky's Rent-a-car
1      3    2      2       7
2      2    2      4       6
3      1    2      2       5
EOD

set key autotitle columnhead
set format x "Day %g"
set xtics 1

plot for [car in "Joanna's Ricky's Mine"] $DATA using 1:car

[Christoph Bersch]

Yes, I agree that this isn't 100% compatible. But processing of apostrophes is not a problem, your example works fine.

s = "Bernadettes' Joanna's Ricky's"
do for [w in s]{ print w }

Output is:

Bernadettes'
Joanna's
Ricky's

Problematic would be if you have an apostrophe at the beginning of a word.

On the other hand, with the current implementation it isn't possible to keep something together which is separated by spaces. With the patch, the follwing works fine:

$DATA << EOD
#Passengers per car
Day  Mine Joanna's Ricky's "Rent a car"
1      3    2      2       7
2      2    2      4       6
3      1    2      2       5
EOD

set key autotitle columnhead
set format x "Day %g"
set xtics 1

plot for [car in "Joanna's Ricky's Mine \"Rent a car\""] $DATA using 1:car

To avoid problems with apostrophes, one could also think about allowing only double quotes.

[Karl Ratzsch]

I think this is another problem that cries for my old wish "array variables" as ideal solution. ;-)

[Ethan Merritt]

OK.
Could you please add an update for the documentation?

[Christoph Bersch]

Hi,

here is an update for the documentation and the stringvar demo. Feel free to correct my english :)

Christoph