Data.String.Interpolation
Documentation
Quasiquote str implements multiline strings with interpolation.
Interpolating a value into the string is done by
$<String expression>$
and interpolating anything with instance Show is
$:<Show expression>$. Due to pretty deep limitations, the parser
is not able to properly deduce associtivity of infix operators,
so use lots and lots of parenthesis.
Repetitive patterns can be made with # symbol:
#<pattern> in <list>: <interpolated string> (|<interpolated string>)#
Where (|<interpolated string>) denotes optional separator for the elements.
Multiline indentation is handled by aligning on smallest un-empty line after the first. Neither pattern matching nor nested #-patterns are supported, however, see example below.
Normal '\\n' style escaping of special characters is intentionally not supported. Please use $endline$ or $n$ style instead.
As an example, let's plot set of vectors with gnuplot:
plotVecs :: [(String,[Double])] -> String
plotVecs vs =
[$str| ## Plot multiple vectors
plot #(n,_) in vs:- with lines lw 5 title $:n$ |, #
#d in map snd vs:$singleVec d$$endline$e$endline$# |]
where
singleVec n = [$str|#(e,i) in zip n [1..]: $:i$ $:e$|$endline$#|]
*Gnuplotter> plotVecs [("A",[1..5]),("B",[2..6])]
# Plot multiple vectors
plot - with lines lw 5 title "A" , - with lines lw 5 title "B"
1 1.0
2 2.0
3 3.0
4 4.0
5 5.0
e
1 2.0
2 3.0
3 4.0
4 5.0
5 6.0
e