Mfcttrf

I am wondering if there is a simple way to expand some input text such as "3-7" as "3,4,5,6,7"?

For context, I am using foreach and want to be able to write

foreach x in 3-7, 9, 14, 52

and have x run through 3, 4, 5, 6, 7, 9, 14, and 52.

Alternatively, if there's an easy way to have

foreach x in 1,3,...7

result in x being defined as "1, 3, 4, 5, 6, and 7" instead of the standard "1, 3, 5, and 7", that would be great.

EDIT: I don't think I was clear in my explanation, but I personally understand how to do these foreach commands in TeX, but wanted a simple input structure for a non-TeX user to use, i.e. typing makeProblems1, 3-7, 9, 14, 52 and having the associated problems as output.

With a little bit of code you can make yourself a parser. I defined makeProblems<integer list><code> for you, in which <integer list> is a comma separated list of numbers where <x>-<y> is parsed as the list of integers between <x> and <y>, inclusive. The function parses the list of numbers and then iterates over the generated list, and makes the current number available for <code> as #1. For example:

makeProblems1,3-7, 9, 14, 52Do something with #1.par

prints:

The code is long because, as the function takes user input, the function takes extra care to make sure that the <integer list> doesn't contain wrong input.

documentclassarticle
usepackagexparse
ExplSyntaxOn
tl_new:N l_ryanj_list_tl
NewDocumentCommand makeProblems m +m 
 
 tl_clear:N l_ryanj_list_tl
 exp_args:Nx clist_map_function:nN #1 __ryanj_parse_item:n
 tl_map_inline:Nn l_ryanj_list_tl #2
 
cs_new_protected:Npn __ryanj_add_item:n #1
 tl_put_right:Nn l_ryanj_list_tl #1 
cs_new_protected:Npn __ryanj_parse_item:n #1
 
 __ryanj_if_number:nTF #1
 __ryanj_add_item:n #1 
 
 str_if_in:nnTF #1 -
 exp_args:Nf __ryanj_parse_range:n tl_to_str:n #1 
 msg_error:nnn ryanj invalid-number #1 
 
 
cs_new_protected:Npn __ryanj_parse_range:n #1
 __ryanj_parse_range:nw #1 #1 q_mark 
cs_new_protected:Npn __ryanj_parse_range:nw #1#2-#3 q_mark
 
 __ryanj_validate_number:nn #1 #2
 __ryanj_validate_number:nn #1 #3
 int_step_function:nnnN #2 1 #3 __ryanj_add_item:n
 use_none:n q_stop
 
cs_new_protected:Npn __ryanj_validate_number:nn #1 #2
 
 __ryanj_if_number:nF #2
 
 msg_error:nnnn ryanj invalid-number-in-range #2 #1
 use_none_delimit_by_q_stop:w
 
 
msg_new:nnn ryanj invalid-range Invalid~range~`#1'. 
msg_new:nnn ryanj invalid-number Invalid~number~`#1'. 
msg_new:nnn ryanj invalid-number-in-range Invalid~number~`#1'~in~range~`#2'. 
prg_new_conditional:Npnn __ryanj_if_number:n #1 T, F, TF 
 
 tl_if_empty:oTF
 tex_romannumeral:D - 0#1 exp_stop_f: 
 
 tl_if_empty:nTF #1
 prg_return_false: 
 prg_return_true: 
 
 prg_return_false: 
 
% For older expl3:
prg_set_protected_conditional:Npnn str_if_in:nn #1#2 T , F , TF 
 
 use:x
 tl_if_in:nnTF tl_to_str:n #1 tl_to_str:n #2 
 prg_return_true: prg_return_false: 
 
ExplSyntaxOff
begindocument
makeProblems1,3-7, 9, 14, 52Do something with #1.par
enddocument

documentclassarticle
usepackagelistofitems,pgffor
newcommandmakeProblems[2]%
 setsepchar,/-%
 readlist*numlist#1%
 defz##1#2par%
 foreachitemzzinnumlist[]%
 ifnumlistlennumlist[zzcnt]=1relaxzzzelse
 itemtomacronumlist[zzcnt,1]tmpA
 itemtomacronumlist[zzcnt,2]tmpB
 foreachzzz in tmpA,...,tmpB%
 zzzz%
 fi
 %

begindocument
makeProblems1,3-7, 9, 14-16, 52Do something with #1.
enddocument

I map the given comma separated list; each item is examined and if it contains a hyphen, a loop is done; in any case, an integer is added to a sequence.

Finally the sequence is expanded with separators between the items; optionally this token list is saved to a macro.

documentclassarticle
usepackagexparse

ExplSyntaxOn

NewDocumentCommandexpandlistom
 
 ryanj_expandlist:n #2 
 IfNoValueTF #1 
 
 ryanj_expandlist_print:
 
 
 ryanj_expandlist_store:N #1
 
 

tl_new:N l_ryan_expandlist_tl
seq_new:N l__ryan_expandlist_seq

cs_new_protected:Nn ryanj_expandlist:n
 
 seq_clear:N l__ryan_expandlist_seq
 clist_map_function:nN #1 __ryan_expandlist_item:n
 tl_set:Nx l_ryan_expandlist_tl
 
 seq_use:Nnnn l__ryan_expandlist_seq ~and~ ,~ ,~and~ 
 
 

cs_new_protected:Nn __ryan_expandlist_item:n
 
 __ryan_expandlist_item:w #1 - - q_stop
 

cs_new_protected:Npn __ryan_expandlist_item:w #1 - #2 - #3 q_stop
 
 tl_if_blank:nTF #2 
 
 seq_put_right:Nn l__ryan_expandlist_seq #1 
 
 
 int_step_inline:nnn #1 #2 seq_put_right:Nn l__ryan_expandlist_seq ##1 
 
 

cs_new:Nn ryanj_expandlist_print:
 
 tl_use:N l_ryan_expandlist_tl
 

cs_new_protected:Nn ryanj_expandlist_store:N
 
 tl_if_exist:NF #1
 
 tl_set_eq:NN #1 l_ryan_expandlist_tl
 
 

ExplSyntaxOff

begindocument

expandlist3-7, 9, 14, 52

expandlist1

expandlist1,4

expandlist1-2

expandlist[foo]3-7, 9, 14, 52

textttmeaningfoo

enddocument