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heredoc-matlab

version 1.0.0 (7.61 KB) by Benjamin Davis
Heredoc solution for MATLAB allowing easy manipulation of multi-line strings

3 Downloads

Updated 15 Dec 2019

GitHub view license on GitHub

A persistent problem with MATLAB is the handling of multi-line strings.
For example, an embedded SQL query:

sql = [
'SELECT * FROM tbl1 ' ...
'INNER JOIN tbl2' ... oops we forgot the last space here
'ON tbl1.id = tbl2.id' newline ... %you could also use a newline if you want
...%add a few where clauses and other features and this will get big fast
'LIMIT 100;'...
]; %phew

This requires copious use of line continuation and quotes. If you were building this query in an external SQL editor/builder, this would require you to add/remove the MATLAB "decoration" to the string every time you moved back and forth.

Many other languages contain a feature called "heredoc/herestring" which allows easy embedding of strings like this with a special syntax. Unfortunately, MATLAB lacks this feature natively.

This tool adds heredoc/herestring capability to MATLAB by allowing these constructs to be embedded in comments using an analogous syntax to the Unix shell and/or Python. The heredoc strings are then accessed by assigning them to a set of structure fields through a call to the "heredoc" function, which parses the current .m file and reads these strings.

For example:
%{
sql_query << END_SQL
SELECT * FROM tbl1 AS t1
INNER JOIN tbl2 AS t2
ON t1.id = t2.t1id
WHERE t1.name = 'John'
AND t2.friend = 'Paul'
ORDER BY birthday
LIMIT 100 OFFSET 50;
END_SQL
%}
hd = heredoc(); %this parses the comments for your heredocs
%requires database toolbox
conn = sqlite(dbfile);
result = conn.fetch(hd.sql_query);

I developed and tested this module on MATLAB 2019b, but it is probably compatible with older versions too. Please let me know if there are any fixes required for backwards compatibility.

Cite As

Benjamin Davis (2020). heredoc-matlab (https://www.github.com/Meisterrichter/heredoc-matlab), GitHub. Retrieved .

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MATLAB Release Compatibility
Created with R2019b
Compatible with any release
Platform Compatibility
Windows macOS Linux