REPL Mode

Start with ccalc (no arguments, stdin is a terminal).

Prompt

The prompt always shows the current value of ans:

[ 0 ]:
[ 42 ]:
[ 0xFF ]:

ans

Every expression result is stored in ans. Expressions that start with an operator use ans as the left-hand operand (partial expressions):

[ 0 ]: 100
[ 100 ]: * 2
[ 200 ]: + 50
[ 250 ]: / 5
[ 50 ]:

REPL commands

Help topics for help <topic>: syntax functions userfuncs testing bases vars script matrices highlight prompt examples

Tab completion

Press Tab in the REPL to complete the current word:

• Variable names defined in the current session.
• Built-in function names (sqrt, mean, assert, …).

When multiple candidates match, they are listed and the longest common prefix is inserted. Press Tab again to cycle or type more characters to narrow down.

>> inv<Tab>       → inv(
>> my_fun<Tab>    → my_function   (if defined)

Inline help for user functions

Place %-comment lines immediately after the function header (MATLAB H1-line style) to attach a doc string. help <name> prints it:

function t = tri(n)
% Return the nth triangular number T(n) = n*(n+1)/2.
% Usage: t = tri(n)
  t = n * (n + 1) / 2;
end

>> help tri
Return the nth triangular number T(n) = n*(n+1)/2.
Usage: t = tri(n)

help <name> searches the current workspace first, then — for functions on the session path — loads the file on demand, so help bisect works even before bisect() has been called.

“Did you mean?” error hints

When a name is not found, ccalc compares it against known variables and built-in names using edit distance. If a close match exists (at most 2 edits), it is shown as a suggestion:

>> sqrtt(4)
Error: Unknown function 'sqrtt'; did you mean 'sqrt'?

>> my_valu + 1
Error: Undefined variable 'my_valu'; did you mean 'my_value'?

Keyboard shortcuts

Silencing a line

Append ; to suppress output. For expressions, ans is still updated. For assignments, ans is never updated regardless of ;.

[ 0 ]: 0.06 / 12;          % expression — ans updated, output suppressed
[ 0.005 ]: rate = 0.07;    % assignment — silent, ans unchanged
[ 0.005 ]:

Multiple ;-separated statements on one line — all but the last are silent:

[ 0 ]: a = 1; b = 2; c = 3;    % all silent
[ 0 ]: a = 1; b = 2             % a = 1 silent, b = 2 shown
b = 2
[ 0 ]:

Configuration

Settings that persist across sessions (precision, default base, prompt) live in config.toml. The config command shows the active values; config reload applies any edits without restarting.

[ 0 ]: config
config file: /home/user/.config/ccalc/config.toml
precision:   10
base:        dec

Syntax highlighting

ccalc highlights the current input line in real time as you type:

Highlighting is active by default. To disable it, set enabled = false in the [highlight] section of config.toml:

[highlight]
enabled = false

To change a colour, add the corresponding key:

[highlight]
keywords = "bold:blue"
numbers  = "color256(208)"
comments = "#808080"

Supported formats: named ("yellow"), 8-bit ("color256(N)"), 24-bit truecolor ("#RRGGBB"), and a "bold:" prefix for any of them. See Configuration for the full reference.

Custom prompt

Edit ~/.config/ccalc/config.toml to customise the prompt:

[repl]
prompt1 = "{gray}({line}){reset} [ {ans} ]: "

Supported placeholders: {ans}, {line}, {user}, {host}, {cwd}, {cwd_short}, {time}, color names ({red}, {green}, {reset}, …), and 24-bit truecolor ({#FF8800}). See Configuration for the full placeholder reference and examples.

History

Input history is saved to ~/.config/ccalc/history and restored on the next session. Each session is marked with a timestamp comment:

% --- Session: 2026-04-01 14:22:07 UTC ---
rate = 0.06 / 12
n = 360
% --- Session: 2026-04-01 15:10:44 UTC ---
hypot(3, 4)

The marker uses % so it is harmless if accidentally recalled and executed.