docs, Kate and VS Code: const, if as a value, """ text, 1e9, str(x, 2), min/max/abs/clamp, import a/b and as, fs, C unions and macros

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016GzNP6r8dg6WDxUVZy8wjL

docs/en/cheatsheet.md

@@ -53,9 +53,10 @@ One statement per line, no semicolons, `{` on the same line, no brackets around
 |---|---|
 | `x := 5` | new variable, type inferred |
 | `int x = 5` | new variable, type written |
-| `int x` | zero / `""` / `[]` / `null` / the struct's defaults |
+| `int x` | zero / `""` / `[]` / `null` / the struct's defaults (also of the structs inside it) |
 | `x = 7` | assign |
 | `x += 1` `-=` `*=` `/=` `%=` | update |
+| `const W = 640`, `const f32 G = 9.8` | a constant (top level of a file; `shapes.W` from a module) |
 
 ---
 
@@ -64,10 +65,10 @@ One statement per line, no semicolons, `{` on the same line, no brackets around
 | Type | Example |
 |---|---|
 | `int` (= `i64`) | `42`, `-7`, `0xFF`, `1_000_000` |
-| `float` (= `f64`) | `3.14` |
+| `float` (= `f64`) | `3.14`, `1e9`, `2.5e-3` |
 | `bool` | `true`, `false` |
 | `char` | `'A'`, `'\n'` |
-| `str` | `"text\t\"quoted\""` |
+| `str` | `"text\t\"quoted\""`, `"""` several lines `"""` (the closing quotes' indentation is removed) |
 | `i8 i16 i32 i64` | signed, sized |
 | `u8 u16 u32 u64` | unsigned, sized |
 | `f32 f64` | floats |
@@ -99,6 +100,7 @@ Escapes: `\n \t \r \0 \\ \" \'`.
 
 ```c
 if a > b { … } else if a == b { … } else { … }
+x := if a > b { a } else { b }  // as a value: one value per branch, else needed
 while x > 0 { … }
 for i in 0..10 { … }          // 0 … 9
 for item in list { … }        // every element (or char of a str)
@@ -234,7 +236,7 @@ Fallible built-ins: `int(s)`, `float(s)`, `read_file`, `write_file`, `delete_fil
 | `s.replace(a, b)` | every a → b |
 | `s.repeat(n)` | n times |
 | `s.bytes()` | `[]u8` |
-| `s.ptr` | `ptr[char]` (for C) |
+| `s.ptr` | `ptr[char]` (for C; a `str` also goes to a `const char *` parameter as it is) |
 | `==` `!=` `<` `>` | compare |
 
 ---
@@ -250,7 +252,8 @@ Fallible built-ins: `int(s)`, `float(s)`, `read_file`, `write_file`, `delete_fil
 | `u8(300)` | `44` (keeps the low bits) |
 | `char(66)` | `'B'` |
 | `bool(0)` | `false` |
-| `str(42)`, `str(1.5)`, `str(true)`, `str('c')` | text |
+| `str(42)`, `str(1.5)`, `str(true)`, `str('c')` | text (a float: the shortest text that is the same number) |
+| `str(3.14159, 2)` | `"3.14"` (that many digits after the point) |
 | `str([1, 2])`, `str(m)`, `str(point)` | the same text `print` shows |
 | `int("x") or 0`, `float(s) or 0.0` | a number, or the fallback |
 | `str(bytes)` | `[]u8` → text |
@@ -273,7 +276,8 @@ Automatic only when nothing is lost: smaller → bigger number, any int → floa
 | `file_exists(path)` | bool |
 | `delete_file(path)` | bool |
 | `shell(command)` | run a command, its exit code |
-| `exit(code)` | stop the program now |
+| `exit(code)` | stop the program now (also ends an `or { }` block) |
+| `min(a, b, …)`, `max(a, b, …)`, `abs(x)`, `clamp(x, lo, hi)` | for any numbers (your own function of that name wins) |
 | `error(message)` | `return error("…")` in a `-> T!` function |
 | `addr(x)` | pointer to x; `addr(fn)` = C callback |
 | `new(value)` | value on the heap → `ptr[T]` |
@@ -311,6 +315,8 @@ import shapes            // shapes.fch next to this file (or in FINCH_PATH)
 shapes.area(b)           // its functions
 shapes.Box(2, 3)         // its structs
 shapes.Box other         // in declarations
+import ui/button         // ui/button.fch: button.draw()
+import ui/button as btn  // another name: btn.draw()
 ```
 
 ---
@@ -334,6 +340,10 @@ shapes.Box other         // in declarations
 | `T *` | `ptr[T]` |
 | `void *`, handles | `ptr` |
 | `T x[N]` (in a struct) | `[N]T` |
+| `union U` | `U`: `U u`, `u.field`, `U(field: v)`, by pointer to C (not by value) |
+| `#define N 4`, `"text"`, `(1u << 3)`, `((Uint64)2)` | constants (not function-like macros) |
+
+A C function's `char *` result is a `str` already; structs by value work on every target (System V, Windows x64, ARM64).
 
 ---
 
@@ -397,9 +407,10 @@ s := Stack[int]()     Stack[int] t     Pair[str, int]("age", 31)         //   ne
 | `path` | `join(a, b)` `base(p)` `dir(p)` `ext(p)` `stem(p)` `parts(p)` `clean(p)` `is_abs(p)` |
 | `time` | `now()` `millis()` `sleep(ms)` `date(t)` `local(t)` `format(t, fmt)` `days_in_month(y, m)` |
 | `proc` | `run(cmd)` `output(cmd)` (fails with its output) `env(name, fallback)` `pid()` `cwd()` |
+| `fs` | `read_bytes(p)` `write_bytes(p, data)` `exists(p)` `is_dir(p)` `mkdir(p)` `list(dir)` `remove_dir(p)` `data_dir(app)` |
 | `json` | `parse(text)` `stringify(v)` `pretty(v)` `new_text/number/bool/null/list/object` `v.get(k)` `v.at(i)` `v.set(k, x)` `v.push(x)` `v.has(k)` `v.str_or(d)` `v.int_or(d)` `v.float_or(d)` `v.bool_or(d)` |
 
 ## Keywords
 
-`fn return if else while for in break continue true false null import link struct enum match defer or try`
+`fn return if else while for in break continue true false null import link struct enum match defer or try const export`
 (and `self` inside methods)

docs/en/for-technicians.md

@@ -214,7 +214,19 @@ x += 1               // also -= *= /= %=
 - Names: ASCII letters, digits and `_`, not starting with a digit. Non-ASCII letters are allowed only inside strings.
   Type names (`int`, `u8`, …), built-in function names and keywords are reserved.
 
-**Keywords:** `fn return if else while for in break continue true false null import link struct defer`
+**Keywords:** `fn return if else while for in break continue true false null import link struct enum match defer or try const export`
+
+### Constants
+
+```c
+const WIDTH = 640
+const HEIGHT = WIDTH / 2          // from other constants
+const f32 GRAVITY = 9.8           // with a type
+const TITLE = "My game"
+```
+
+A constant is written at the top level of a file, next to the functions, and can't be changed. It is made of
+numbers, text, `true`/`false`, chars, other constants and operators; a module's constant is `shapes.SIDES`.
 
 ---
 
@@ -316,6 +328,13 @@ Notes:
 
 ## 8. Control flow
 
+`if` can also give a value; each branch holds one value, and the `else` is needed:
+
+```c
+label := if score > 100 { "high" } else if score > 10 { "mid" } else { "low" }
+f32 speed = if running { 2.5 } else { 1.0 }
+```
+
 ```c
 if x > 10 {
     ...
@@ -485,7 +504,21 @@ s[0] = 'J'                // change a character
 | `s.ptr` | a `ptr[char]` for C (valid while `s` lives) |
 
 `str` keeps its length, so `.len` is instant, and it is always NUL-terminated, so passing it
-to C as `char*` works.
+to C as `char*` works. The other way round, a C function that gives back a `char *` gives you a `str`
+(a copy is made when you keep it), and `str(p)` reads a `ptr[char]` you got some other way.
+
+Text over several lines goes between `"""`. The line break after the opening quotes is dropped, and so is the
+indentation of the closing quotes, from every line, so the text can be indented with your code:
+
+```c
+shader := """
+    #version 330
+    void main() { gl_Position = vec4(0.0); }
+    """
+```
+
+Numbers as text: `str(x)` is the shortest text that reads back as the same number (`0.1`, `0.30000000000000004`,
+`1e+20`); `str(x, 2)` always has two digits after the point (`3.14`).
 
 ---
 
@@ -642,6 +675,8 @@ fn main() {
 
 - Everything in a module is used with the module's name in front: `shapes.area`, `shapes.Box`.
 - A module doesn't have `main`. Modules can import other modules.
+- Modules in folders: `import ui/button` loads `ui/button.fch` and is used as `button.draw()`.
+- Another name: `import ui/button as btn` → `btn.draw()`. Two imports can't use the same name.
 
 ---
 
@@ -742,8 +777,10 @@ Both work directly; `examples/opengl.fch` and `examples/vulkan.fch` are complete
 
 ### What does not work yet
 
-- C **unions** by value, and structs with **bit fields** by value (pointers to them work).
-- **Function-like macros** and macros that are not a single number.
+- C **unions** and structs with **bit fields** passed to or returned from a C function **by value** (pointers to them
+  work, and so do unions as variables: `SDL_Event e`, `e.type`, `e.key.key`, `SDL_PollEvent(addr(e))`).
+- **Function-like macros** (`#define MAX(a, b) ...`) and macros that make a struct (raylib's `RAYWHITE`).
+  Macros that are a number, a text or an expression of them (`(1u << 3)`, `((Uint64)1)`, `(A | B)`) work.
 - `long double`, 128-bit integers.
 
 ---
@@ -1035,6 +1072,10 @@ library's second, so your own file of the same name wins.
 | `time` | `now()`, `millis()` (a clock for measuring), `sleep(ms)`, `date(t)`, `local(t)`, `format(t, "%Y-%m-%d")`, `days_in_month` |
 | `proc` | `run(cmd)` (the exit code), `output(cmd)` (what it printed; an error if it failed), `env(name, fallback)`, `pid()`, `cwd()` |
 | `json` | `parse(text)`, `stringify(v)`, `pretty(v)`, and the value type `Json` with `get`, `at`, `set`, `push`, `has`, `str_or`, `int_or` ... |
+| `fs` | `read_bytes(p)` / `write_bytes(p, data)` (`[]u8`, any bytes), `exists`, `is_dir`, `mkdir` (with the folders above), `list` (sorted names), `remove_dir`, `data_dir(app)` (a folder for the user's saves) |
+
+`min(a, b, ...)`, `max(a, b, ...)`, `abs(x)` and `clamp(x, lo, hi)` work on any numbers without an import (a function of
+your own with the same name wins).
 
 ```
 import json