<seq>  (<col>)  C 
<seq.>  (<seq> <col.>)  C 
 immutable sequence.  
1st  (x<seq> => <any>)  G 
 == (elt x 0)  
2nd  (x<seq> => <any>)  G 
 == (elt x 1)  
3rd  (x<seq> => <any>)  G 
 == (elt x 2)  
last  (x<seq> => <any>)  G 
 == (elt x ( (len x) 1))  
pos  (x<seq> v<any> => (t? <int>))  G 
 finds position of v in x else returns false.  
finds  (x<seq> y<seq> => (t? <int>))  G 
 finds position of y in x else returns false.  
add  (x<seq> y<any> => <seq>)  M 
 returns sequence with y added to the end of x.  
push  (x<seq> y<any> => <seq>)  G 
 returns sequence with y added to x.  
pop  (x<seq> => (tup <any> <seq>))  G 
 returns last pushed element of x and new sequence with that
element removed from x.  
rev  (x<seq> => <seq>)  G 
 returns reversed sequence.  
cat  (x<seq> more... => <seq>)  G 
 returns concatenated sequences.  
sub  (x<seq> from<int> below<int> => <seq>)  G 
 subsequence of x between from and below.  
'[' ... ']'  '[' ,x ,from ,below ']'  S 
 == (sub ,x ,from ,below)  
sub*  (x<seq> from<int> => <seq>)  G 
 == (sub x from (len x))  
'[' ... ']'  '[' ,x ,from * ']'  S 
 == (sub* ,x ,from)  
ins  (x<seq> val i<int> => <seq>)  G 
 returns copy of x's with val inserted before i.  
deldups  (x<seq> => <seq>)  G 
 returns sequence with all duplicates removed.  
delvals  (s<seq> val => <seq>)  G 
 returns sequence with all copies of val removed.  
sortby  (s<seq> f<fun> => <seq>)  G 
 returns a sorted copy of s using f as a comparator.  
sort  (s<seq> => <seq>)  G 
 == (sortby s <)  
pick  (f<fun> x<seq> => <seq>)  G 
 returns new sequence with elements corresponding to
nonfalse results when calling predicate f.  
prefix?  (x<seq> prefix<seq> => <log>)  G 
 returns true iff sequence x starts with sequence prefix.  
suffix?  (x<seq> suffix<seq> => <log>)  G 
 returns true iff sequence x ends with sequence suffix.  
repeat  (x<seq> n<int> => <seq>)  G 
 returns sequence with n concatenated copies of x.  
split  (x<seq> sep => <seq>)  G 
 returns sequence of subsequences of x separated by sep.  
join  (xs<seq> sep<seq> => <seq>)  G 
 returns sequence composed of sequences in xs joined with
sep.  
