What was the first compiler/interpreter/assembler to indicate problematic columns in diagnostic messages?

Question

These days, most compilers and interpreters seem to provide the following in diagnostics:

• A description of the problem
• The name of the source file
• A line number
• A relevant position within the line
• The text of the line
• An indication of where the relevant position is in the line's text

In earlier systems, diagnostic printouts often consisted, from what I can tell, of a message or error code and the text of an offending card or line. All that is really missing is the precise indication of where on the card or line the problem was found.

I was somewhat surprised to see that the Pascal P-series of compilers, as far back as P2 from 1974, provided almost everything that modern systems do:

• An error code
• A line number
• The text of the line (albeit as a side effect of listing the source code)
• An indication of where the relevant position is in the line's text

(See the routines error and endofline. The file name was implicit, since only one file was ever being compiled.)

Did any systems predating P2 do this (or better, e.g. by indicating a range of positions as in GCC and Clang)? LISP 1.5 seems to have been close, having a function error1 that was designed for this exact purpose (printing a line of text along with a “cursor”), although the interpreter never actually used it!

Answer 1

Printing a mere column number seems like a step backwards. The Whetstone Algol compiler (1963, if memory serves) told you the line number and delimiter that were problematic, as well as (of course) an error code and the line in question.

FAIL 133
LINE   6    
DELIMITER [̲
IDENTIFIER writetex
BECAUSE OF LINE   2

Underlined bracket, shown as 2 separate characters on modern ASCII equipment but not on the contemporaneous Flexowriter, was a string quote in this Algol dialect.

Error 133 means we ran off the end of the program text at line 6, in this case because of a missing closing string quote. The opening string quote was on line 2, just after the identifier writetext (this dialect considered only 8 characters to be significant).

So, my answer to the question is another question – didn't they always do this? (Depends on implementation, of course, and how much attention was paid to diagnostics. The Walgol guys were pretty keen on diagnosability).

---

KDF9 was oriented to paper tape rather than cards, and paper tape people don't really think in terms of column numbers, so a raw column number wouldn't have really helped anyway. On the other hand, converting "column N" to N−1 spaces and an up-arrow on the listing, underneath the listing of the offending line, is decidedly better.

SNOBOL4, developed in the early 1960s at Bell Labs, initially on IBM System/360, used that particular technique.

Section 10.1.5 in The SNOBOL4 programming language, the definitive description of SNOBOL4, shows that the error indicator was a (vertical) apostrophe. Likely that particular listing was from SNOBOL on an S/360.

X = A+B
    '  
*** ILLEGAL CHARACTER IN EXPRESSION

(Operators needed to be offset by spaces or other delimiters)

At the time SNOBOL4 was developed, it was very much a card-oriented language, though it had no particular column requirements except for column 1 having special meaning (labels and comments), and of course a 72-columm limit.

This example shows that error-location to a column was already a known technique in the 1960s, though of course this is the 'pointer in column' approach rather than 'print column N' approach.

---

(I removed the FORTRAN example, since although it demonstrated a good level of error diagnosis, it's not really relevant to the point of location by specific column).