here's the relevant code
[ %n = name of a column from the users list ]

/* find the column name in the list */
j=1;
colnum = -1;
for (j=1; j <= wks.nCols ; j+=1) {
wks.col = j;
%g=wks.col.name$;
type %n %g $(j);
if(%n==%g) {
colnum = j;
type (^^);
};

When I run this on worksheet with cols A B C D, i see:
(When %n="B")
B A 1
B B 2
^^
B C 3
B D 4
B E 5

(then the script adds column B2 and tries to find column C)
C A 1
C B 2
C B2 3
C C 4
^^
C D 5
C E 6
^^

(So the script adds a column C2 where it made the last match, ie at the end
then tries to find column D)

When you are comparing strings, you must use double quotes on the right-hand
side of the condition.

For example:

if(%N=="%G") type "same";

%a=result';
%b=result;

if ("%a"=="%b'") type yes;

%a=result';
%b=result;

if (%a==%b) type yes; else type no;
if (%a==%b') type yes; else type no;
if (%a=="%b'") type yes; else type no;
if (%b'=="%a") type yes; else type no;
if ("%b'"=="%a") type yes; else type no;

%a=result.;
%b=result;

if (%a=="%b.") type yes; else type no;
if (%b.=="%a") type yes; else type no;
if ("%b."=="%a") type yes; else type no;