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rswier
c4
C2014–2025
rswier / c4

c4

C in four functions

Explore on GitHubRead Hacker News discussions
25Distinct people
31Mentions
1Explicit recommenders
10.8KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

C in four functions

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

Yes. Obligatory and tedious re-up for my favorite minimalistic C program of the last 5 years: https://github.com/rswier/c4 Take 2 hours to grok this and you can skip compiler…

tptacek used a recommendation phrase. One indexed comment matches. This is a phrase match, not a verdict.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 6:01:32 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year31 dated mentions

Observed mentions: 2014-11-04 20:19:58 UTC to 2025-09-30 16:17:51 UTC.

0123452014-01-01 00:00:00 UTC to 2015-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments20142015-01-01 00:00:00 UTC to 2016-01-01 00:00:00 UTC (exclusive): 5 mentions; 0 submissions, 5 comments2016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 3 mentions; 2 submissions, 1 comments2017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 4 mentions; 0 submissions, 4 comments20192020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 4 mentions; 1 submissions, 3 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments2025

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20142014-01-01 00:00:00 UTC2015-01-01 00:00:00 UTC211
20152015-01-01 00:00:00 UTC2016-01-01 00:00:00 UTC505
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC321
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC101
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC303
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC404
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC211
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC202
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC101
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC413
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC211
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC211

From the project README

An excerpt from the repository, fetched Nov 13, 2026.

Read the project’s introduction
c4 - C in four functions An exercise in minimalism. Try the following: gcc -o c4 c4.c ./c4 hello.c ./c4 -s hello.c ./c4 c4.c hello.c ./c4 c4.c c4.c hello.c
Read the full README on GitHub

What Hacker News says

5 sources
userbinator·Jun 9, 2015
I assume you posted this looking for feedback, so here is my advices: - A 16-line main.c with a single function that does almost nothing is annoying to say the least; this application is simple enough that I think it really shouldn't be more than a single file. - You really don't need to use dynamic allocation for this. Try a simpler algorithm like recursive-descent/precedence climbing, and tokenise+evaluate as you go. - isSymbol()/getSymbol() should be merged into one function - you are doing duplicate work here since once you know that it is one of those special identifiers, you should be able to return the value immediately instead of doing another set of comparisons. This is an almost-complete C interpreter in roughly the same number of lines of code as your calculator, but its structure is actually much simpler. It's probably a bit f
Read the rest
ar toward the side of terseness, but good to study in any case: https://github.com/rswier/c4/blob/master/c4.c For understanding precedence climbing/recursive descent, this is a good article: https://www.engr.mun.ca/~theo/Misc/exp_parsing.htm One thing I see with a lot of beginners is a tendency to overcomplicate solutions, writing far more code than necessary. It takes practice to avoid this, but giving them some extremely minimal implementations to study can help them to better understand the essence of the problem and its solution; to a beginner, it is often simpler than they seem to be at first glance.
In Show HN: Calc, a simple command-line calulator in C

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