Help evaluating patterns in templates

v2: Troubleshooting
1

Hi all. I’d be grateful if somone could point out where i’m going wrong using substrings within the following template, which works except that i cannot get the output to sort by a gsub output.

${template.each(query[[
from index.tag "composer" 
order by string.gsub(_.nameFull, '.*% ','')]], template.new[==[
    * **[[${name}]]** ${_.nameFull:gsub('.*% ','')} ${string.gsub(_.nameFull, '.*% ','')} (born ${string.sub(_.dateBirth, 1, 4)}) 
    ]==])}

Frontmatter of a sample page :

---
dateBirth: '1918-08-25'
nameFull: 'Leonard Bernstein'
tags: conductor, composer, pianist
---

#person

a snippet of output shows that both gsub formulations (to grab just the surname from fullName) are working in the output. However i can’t work out how to use either of them to sort the output:

image
image781×195 27.6 KB

Interestingly, if i extract year from dateBirth then the following will get correct chronological sorting:

order by string.sub(_.dateBirth, 1, 4)

No doubt some simple mistake, I hope the above isn’t too convoluted and I hope someone can set me right.

Despite this hiccup, even (or because?) i have no experience with either, I’m finding Lua easier than JavaScript and enjoying having switched to v2.

Thanks @zef and to everyone for the posts here which are very helpful.

2

If you run the query and select the gsub value, you can see that it is returning the resulting string and some count that I don’t understand (it doesn’t appear to be the number of substitutions, which is what I would expect):

${query[[
from p = index.tag "composer"
select string.gsub(p.nameFull, '.*% ', '')
]]}
values
{Beethoven, 1}
{Bernstein, 1}
{Madetoja, 1}

You can see in the first example of the String API how it is handling the return values.

I suspect it is having trouble sorting those pairs of values. You might try adding a function to string to do what you want and reference that instead:

string.lastWord = function (s)
  match, _ = string.gsub(s, '.*% ', '')
  return match
end

${query[[
from p = index.tag "composer"
order by string.lastWord(p.nameFull)
select string.lastWord(p.nameFull)
]]}
1 Like
3

aaah, thanks very much for directing me so helpfully. I’ll work through this when i’ve got a moment in the next few days. Much appreciated

1 Like