Comments and prose lines
You will learn
Where each kind of note may stand, and the one line that breaks the parser.
A line that starts with a semicolon is prose: the compiler skips the rest of the line. Prose lines stand at the top level, between declarations. Two slashes start a comment anywhere, after code or inside a test. One trap: a semicolon alone on its line is not an empty prose line, it is a parse error, and the whole spec fails. Put a word after it, or leave the line empty.
Try it
Add a line with a lone semicolon to the lesson spec in the player, read the error, then remove it.
Prose lines, slash comments and the lone semicolon that breaks a t27 spec, each checked with the real compiler. Lesson 3 of the t27 basics course.
specs/basics/03_comments_and_prose.t27
// SPDX-License-Identifier: Apache-2.0
; t27 basics, lesson 3: Comments and prose lines.
; Two kinds of notes: a semicolon line of prose, and a comment after two slashes.
module basics_03_comments_and_prose;
; A prose line starts with a semicolon and must carry words.
// Two slashes start a comment anywhere, also after code.
pub const PROSE_NEEDS_WORDS : bool = true; // a trailing comment
test comments_change_nothing {
// a comment inside a test
assert PROSE_NEEDS_WORDS == true;
}
All lessons
Module 1 · A spec file
What a .t27 file holds: a module line, prose lines and comments.
Module 2 · Values and types
Constants, the width of a whole number, and true, false and text.
Module 3 · Arrays, trits and expressions
Lists of values, the three values of a trit, and what operators compute.
Module 4 · Tests and functions
A test block, several small tests in one spec, and a function with typed inputs.
Module 5 · Inside a function
Names with let and var, choices with if and switch, and loops.
Module 6 · Visibility and your own types
What pub shares with other modules, and the structs and enums you declare.
Module 7 · Modules, rules and gen-ts
Reading another module, stating a rule that always holds, and a spec turned into TypeScript.
Module 8 · The compiler and tri
The backends t27c writes, the stages it reads a spec in, and the tri command.
Module 9 · Errors, a program, what next
Reading a compiler error, one small complete program, and the course to take next.