plpgsql code doen't work

[janek12@xxxxxx]

Hi, 
 
I found following code:

create or replace function plpgsql_edit_distance(stra text, strb text)
	returns integer as $$
declare
    rows integer;
    cols integer;
begin
    rows := length(stra);
    cols := length(strb);

    IF rows = 0 THEN
    	return cols;
    END IF;
    IF cols = 0 THEN
	return rows;
    END IF;

    declare
	row_u integer[];
	row_l integer[];
	diagonal integer;
	upper integer;
	left integer;
    begin
	FOR i in 0..cols LOOP
	    row_u[i] := i;
	END LOOP;

	FOR i IN 1..rows LOOP
	    row_l[0] := i;
	    FOR j IN 1..cols LOOP
	        IF substring (stra, i, 1) = substring (strb, j, 1) THEN
		    diagonal := row_u[j-1];
		else
		    diagonal := row_u[j-1] + 1;
		END IF;
		upper := row_u[j] + 1;
		left := row_l[j-1] + 1;
		row_l[j] := int4smaller(int4smaller(diagonal, upper), left);
		END LOOP;
            row_u := row_l;
	END LOOP;
	return row_l[cols];
    end;
end
$$ language 'plpgsql' immutable strict;

Does anyone know why the colums :"row_l[j] := int4smaller(int4smaller(diagonal, upper), left);" doesn't work.
 
Janek Sendrowski


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