Mark Di Marco
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markmarkoh.bsky.social
Mark Di Marco
@markmarkoh.bsky.social
36 followers 64 following 12 posts
Early stage startup engineer and engineering leader, currently VP of Eng at Buildforce.

Recording episodes of a new show called Commit History, which explores interesting commit on interesting open source projects

https://markmarkoh.com
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markmarkoh.bsky.social
Is this vibe coding? Asking for a friend.
April 12, 2025 at 12:26 AM
markmarkoh.bsky.social
The Day 1 #AdventOfCode solution we've all been waiting for: COBOL

65 years ago a committee met in the Pentagon to standardize a new programming language, and soon COBOL-60 was born.

Can you guess the name of the sorting algorithm used in the SORT-ARRAYS procedure?

adventofcode.com/2024/day/1
Screenshot of code Preamble in COBOL: IDENTIFICATION DIVISION. PROGRAM-ID. NUMBER-PAIRING. ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT INPUT-FILE ASSIGN TO "INPUT.TXT" ORGANIZATION IS LINE SEQUENTIAL. DATA DIVISION. FILE SECTION. FD INPUT-FILE. 01 INPUT-LINE. 05 LEFT-NUM PIC X(5). 05 FILLER PIC X(3). 05 RIGHT-NUM PIC X(5). WORKING-STORAGE SECTION. 01 WS-ARRAYS. 05 LEFT-ARRAY OCCURS 1000 TIMES PIC S9(5). 05 RIGHT-ARRAY OCCURS 1000 TIMES PIC S9(5). 01 WS-VARIABLES. 05 EOF-FLAG PIC X VALUE 'N'. 05 ARRAY-SIZE PIC 9(4) VALUE 0. 05 TOTAL-DIST PIC 9(8) VALUE 0. 05 TEMP-NUM PIC S9(5). 05 I PIC 9(4). 05 J PIC 9(4). 05 DIFF PIC S9(5). PROCEDURE DIVISION. MAIN-PROCEDURE. DISPLAY "=== STARTING PROGRAM ===" OPEN INPUT INPUT-FILE PERFORM READ-NUMBERS UNTIL EOF-FLAG = 'Y' CLOSE INPUT-FILE DISPLAY "=== SORTING ARRAYS ===" PERFORM SORT-ARRAYS DISPLAY "=== CALCULATING DISTANCES ===" PERFORM CALCULATE-DISTANCE DISPLAY "=== FINAL RESULT ===" DISPLAY "TOTAL DISTANCE: " TOTAL-DIST STOP RUN. Screenshot of main procedures in COBOL for day 1 of advent of code solution: READ-NUMBERS. READ INPUT-FILE AT END MOVE 'Y' TO EOF-FLAG NOT AT END ADD 1 TO ARRAY-SIZE MOVE FUNCTION NUMVAL(LEFT-NUM) TO LEFT-ARRAY(ARRAY-SIZE) MOVE FUNCTION NUMVAL(RIGHT-NUM) TO RIGHT-ARRAY(ARRAY-SIZE) END-READ. SORT-ARRAYS. PERFORM VARYING I FROM 1 BY 1 UNTIL I > ARRAY-SIZE - 1 PERFORM VARYING J FROM 1 BY 1 UNTIL J > ARRAY-SIZE - I IF LEFT-ARRAY(J) > LEFT-ARRAY(J + 1) MOVE LEFT-ARRAY(J) TO TEMP-NUM MOVE LEFT-ARRAY(J + 1) TO LEFT-ARRAY(J) MOVE TEMP-NUM TO LEFT-ARRAY(J + 1) END-IF IF RIGHT-ARRAY(J) > RIGHT-ARRAY(J + 1) MOVE RIGHT-ARRAY(J) TO TEMP-NUM MOVE RIGHT-ARRAY(J + 1) TO RIGHT-ARRAY(J) MOVE TEMP-NUM TO RIGHT-ARRAY(J + 1) END-IF END-PERFORM END-PERFORM. CALCULATE-DISTANCE. PERFORM VARYING I FROM 1 BY 1 UNTIL I > ARRAY-SIZE COMPUTE DIFF = LEFT-ARRAY(I) - RIGHT-ARRAY(I) IF DIFF < 0 COMPUTE DIFF = DIFF * -1 END-IF ADD DIFF TO TOTAL-DIST END-PERFORM.
December 1, 2024 at 6:58 PM
markmarkoh.bsky.social
I look for commits in all sorts of programming languages, and so far throughout my research, Zig has been my favorite “new” language that not enough people are talking about.

Here were a few patterns from my Bun.sh episode that stuck out:

@ziglang.bsky.social
December 1, 2024 at 3:20 PM