// SPDX-License-Identifier: Apache-2.0
; specs/widgets/golden-gft8.t27 -- the infographic of lesson 24 of the GoldenFloat course (specs/course/goldenfloat.t27)
; Source of truth for public/widgets/golden-gft8/ (gHashTag/trinity): scripts/widget-pages-from-spec.mjs compiles
; this file, checks its constants, evaluates the tests below and writes the page. tool.js is one import of
; ../infographic.js, which draws SAY_TABLE_* as a real <table> and SAY_FLOW_* as an SVG diagram with a
; <title>, black and white, and holds no words of its own. ASCII only (L3), English only (LANG-EN).
; The lesson spec it illustrates: public/t27/files/specs/numeric/gft8.t27.
; phi^2 + 1/phi^2 = 3 | TRINITY

module widget_golden_gft8;

pub const KIND : str = "widget-tool";
pub const ID : str = "golden-gft8";
pub const TITLE : str = "GoldenFloat 24: GF-T8, an exponent in trits";
pub const DESCRIPTION : str = "GF-T8 as the spec lays it out, read from gft8.t27. Lesson 24 of the GoldenFloat course.";
pub const IMAGE_ALT : str = "A black and white table, GF-T8 as the spec lays it out: Sign, 1 bit, SIGN_BITS; Exponent, 3 trits, EXP_TRITS; Mantissa, 4 bits, MANT_BITS; Offset, 13, EXP_OFFSET; Non-finite offset, 26, OFFSET_MAX; Exponent values, 27, exp_values().";
pub const HOOK : str = "Three exponent trits give 27 values, balanced around zero by an offset of 13.";
pub const CATEGORY : str = "compiler";
pub const DATA_SOURCES : [2]str = ["The lesson spec public/t27/files/specs/numeric/gft8.t27, read when the course was authored; every number in the table is a constant, a test value or arithmetic of that file", "Nothing on this page was measured on hardware or timed; a value written into a test is said to be written in, not computed"];
pub const READS_LOCAL_FILES : bool = false;
pub const SENDS_NOTHING : bool = true;

; --- The table -----------------------------------------------------------------------------
pub const SAY_TABLE_CAPTION : str = "GF-T8 as the spec lays it out";
pub const SAY_TABLE_HEAD : [3]str = ["Field", "Value", "Spec constant"];
pub const SAY_TABLE_CELLS : [18]str = ["Sign", "1 bit", "SIGN_BITS", "Exponent", "3 trits", "EXP_TRITS", "Mantissa", "4 bits", "MANT_BITS", "Offset", "13", "EXP_OFFSET", "Non-finite offset", "26", "OFFSET_MAX", "Exponent values", "27", "exp_values()"];
pub const K_TABLE_COLS : u8 = 3;
pub const K_TABLE_ROWS : u8 = 6;
pub const K_TABLE_CELLS : u16 = 18;

; --- The diagram and the note ----------------------------------------------------------------
pub const SAY_FLOW_TITLE : str = "Balanced exponents";
pub const SAY_FLOW_STEPS : [3]str = ["3 trits: 27 values", "offset 13 centres them", "offset 26 is not finite"];
pub const K_FLOW_STEPS : u8 = 3;
pub const SAY_NOTE : str = "gft8.t27 tests 1 + 3 + 4 = 8, E / M = 750 thousandths, and OFFSET_MAX = 2 x EXP_OFFSET.";

test the_cells_fill_whole_rows {
    assert K_TABLE_ROWS * K_TABLE_COLS == K_TABLE_CELLS;
}

test the_table_has_a_body {
    assert K_TABLE_ROWS > 0;
    assert K_TABLE_COLS > 0;
}

test the_diagram_has_every_step {
    assert K_FLOW_STEPS == 3;
    assert K_FLOW_STEPS > 1;
}