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Formatting and Printing

The runtime prints values with print and print_end, builds strings with fmt, and reads user input with input.

#include "abscom/abs.h"

Printing

print and print_end are variadic: each argument is stringified and joined with a single space.

Function Description
print(...) Print each argument (space-separated) followed by a newline.
print_end(const char *end, ...) Print each argument followed by the custom end string. 
abs_init();

var name = abs_new_str("Ada");
print(v("Hello,"), name, v("!"));        /* Hello, Ada !   */

print_end("", v("no newline"));          /* no trailing newline */
print_end(", ", v("a"), v("b"));         /* a, b,           */

Formatting

Function Description
fmt(const char *format, ...) Build a string; every {} placeholder consumes one var argument.

fmt is not printf-style: placeholders are literal {} braces, and arguments are var objects stringified with to_str:

var out = fmt("Hello, {}! You have {} messages.", name, v(3));
print(out);                 /* Hello, Ada! You have 3 messages. */

Input

Function Description
var input(const char *prompt) Print the prompt, read a line from stdin, return it as a string. 
var answer = input("Your name? ");
print(fmt("Hi {}", answer));

How values stringify

  • Int — decimal digits (42).
  • Float — two decimals (3.14, 2.00).
  • Str — the raw text (no quotes).
  • Bool — True / False.
  • None — None.
  • List — [item, item] with items stringified recursively.
  • Dict — {key: value, ...}.
  • Set — {item, item, ...}.
  • Error — Error: <message> when printed; to_str yields just the message.
  • Class / Instance — <class 'name'> / <name object>.
  • File — <file>.

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