chore: Add docs for each comptime method (#5802)

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

Adds docs for each comptime method that's been added.

## Additional Context



## Documentation\*

Check one:
- [ ] No documentation needed.
- [x] Documentation included in this PR.
- [ ] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

---------

Co-authored-by: TomAFrench <tom@tomfren.ch>
Co-authored-by: Maxim Vezenov <mvezenov@gmail.com>

cspell.json

@@ -119,6 +119,7 @@
         "keccakf",
         "krate",
         "libc",
+        "Linea",
         "losslessly",
         "lvalue",
         "Maddiaa",
@@ -220,8 +221,7 @@
         "wasi",
         "wasmer",
         "Weierstraß",
-        "zshell",
-        "Linea"
+        "zshell"
     ],
     "ignorePaths": [
         "./**/node_modules/**",

docs/docs/noir/standard_library/meta/expr.md

@@ -0,0 +1,149 @@
+---
+title: Expr
+---
+
+`std::meta::expr` contains methods on the built-in `Expr` type for quoted, syntactically valid expressions.
+
+## Methods
+
+### as_array
+
+#include_code as_array noir_stdlib/src/meta/expr.nr rust
+
+If this expression is an array, this returns a slice of each element in the array.
+
+### as_integer
+
+#include_code as_integer noir_stdlib/src/meta/expr.nr rust
+
+If this element is an integer literal, return the integer as a field
+as well as whether the integer is negative (true) or not (false).
+
+### as_binary_op
+
+#include_code as_binary_op noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a binary operator operation `<lhs> <op> <rhs>`,
+return the left-hand side, operator, and the right-hand side of the operation.
+
+### as_block
+
+#include_code as_block noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a block `{ stmt1; stmt2; ...; stmtN }`, return
+a slice containing each statement.
+
+### as_bool
+
+#include_code as_bool noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a boolean literal, return that literal.
+
+### as_comptime
+
+#include_code as_comptime noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a `comptime { stmt1; stmt2; ...; stmtN }` block,
+return each statement in the block.
+
+### as_function_call
+
+#include_code as_function_call noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a function call `foo(arg1, ..., argN)`, return
+the function and a slice of each argument.
+
+### as_if
+
+#include_code as_if noir_stdlib/src/meta/expr.nr rust
+
+If this expression is an `if condition { then_branch } else { else_branch }`,
+return the condition, then branch, and else branch. If there is no else branch,
+`None` is returned for that branch instead.
+
+### as_index
+
+#include_code as_index noir_stdlib/src/meta/expr.nr rust
+
+If this expression is an index into an array `array[index]`, return the
+array and the index.
+
+### as_member_access
+
+#include_code as_member_access noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a member access `foo.bar`, return the struct/tuple
+expression and the field. The field will be represented as a quoted value.
+
+### as_repeated_element_array
+
+#include_code as_repeated_element_array noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a repeated element array `[elem; length]`, return
+the repeated element and the length expressions.
+
+### as_repeated_element_slice
+
+#include_code as_repeated_element_slice noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a repeated element slice `[elem; length]`, return
+the repeated element and the length expressions.
+
+### as_slice
+
+#include_code as_slice noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a slice literal `&[elem1, ..., elemN]`,
+return each element of the slice.
+
+### as_tuple
+
+#include_code as_tuple noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a tuple `(field1, ..., fieldN)`,
+return each element of the tuple.
+
+### as_unary_op
+
+#include_code as_unary_op noir_stdlib/src/meta/expr.nr rust
+
+If this expression is a unary operation `<op> <rhs>`,
+return the unary operator as well as the right-hand side expression.
+
+### as_unsafe
+
+#include_code as_unsafe noir_stdlib/src/meta/expr.nr rust
+
+If this expression is an `unsafe { stmt1; ...; stmtN }` block,
+return each statement inside in a slice.
+
+### has_semicolon
+
+#include_code has_semicolon noir_stdlib/src/meta/expr.nr rust
+
+`true` if this expression is trailed by a semicolon. E.g.
+
+```
+comptime {
+    let expr1 = quote { 1 + 2 }.as_expr().unwrap();
+    let expr2 = quote { 1 + 2; }.as_expr().unwrap();
+
+    assert(expr1.as_binary_op().is_some());
+    assert(expr2.as_binary_op().is_some());
+
+    assert(!expr1.has_semicolon());
+    assert(expr2.has_semicolon());
+}
+```
+
+### is_break
+
+#include_code is_break noir_stdlib/src/meta/expr.nr rust
+
+`true` if this expression is `break`.
+
+### is_continue
+
+#include_code is_continue noir_stdlib/src/meta/expr.nr rust
+
+`true` if this expression is `continue`.

docs/docs/noir/standard_library/meta/function_def.md

@@ -0,0 +1,55 @@
+---
+title: FunctionDefinition
+---
+
+`std::meta::function_def` contains methods on the built-in `FunctionDefinition` type representing
+a function definition in the source program.
+
+## Methods
+
+### name
+
+#include_code name noir_stdlib/src/meta/function_def.nr rust
+
+Returns the name of the function.
+
+### parameters
+
+#include_code parameters noir_stdlib/src/meta/function_def.nr rust
+
+Returns each parameter of the function as a tuple of (parameter pattern, parameter type).
+
+### return_type
+
+#include_code return_type noir_stdlib/src/meta/function_def.nr rust
+
+The return type of the function.
+
+### set_body
+
+#include_code set_body noir_stdlib/src/meta/function_def.nr rust
+
+Mutate the function body to a new expression. This is only valid
+on functions in the current crate which have not yet been resolved.
+This means any functions called at compile-time are invalid targets for this method.
+
+Requires the new body to be a valid expression.
+
+### set_parameters
+
+#include_code set_parameters noir_stdlib/src/meta/function_def.nr rust
+
+Mutates the function's parameters to a new set of parameters. This is only valid
+on functions in the current crate which have not yet been resolved.
+This means any functions called at compile-time are invalid targets for this method.
+
+Expects a slice of (parameter pattern, parameter type) for each parameter. Requires
+each parameter pattern to be a syntactically valid parameter.
+
+### set_return_type
+
+#include_code set_return_type noir_stdlib/src/meta/function_def.nr rust
+
+Mutates the function's return type to a new type. This is only valid
+on functions in the current crate which have not yet been resolved.
+This means any functions called at compile-time are invalid targets for this method.

docs/docs/noir/standard_library/meta/index.md

@@ -0,0 +1,141 @@
+---
+title: Metaprogramming
+description: Noir's Metaprogramming API
+keywords: [metaprogramming, comptime, macros, macro, quote, unquote]
+---
+
+`std::meta` is the entry point for Noir's metaprogramming API. This consists of `comptime` functions
+and types used for inspecting and modifying Noir programs.
+
+## Functions
+
+### type_of
+
+#include_code type_of noir_stdlib/src/meta/mod.nr rust
+
+Returns the type of a variable at compile-time.
+
+Example:
+```rust
+comptime {
+    let x: i32 = 1;
+    let x_type: Type = std::meta::type_of(x);
+
+    assert_eq(x_type, quote { i32 }.as_type());
+}
+```
+
+### unquote
+
+#include_code unquote noir_stdlib/src/meta/mod.nr rust
+
+Unquotes the passed-in token stream where this function was called.
+
+Example:
+```rust
+comptime {
+    let code = quote { 1 + 2 };
+
+    // let x = 1 + 2;
+    let x = unquote!(code);
+}
+```
+
+### derive
+
+#include_code derive noir_stdlib/src/meta/mod.nr rust
+
+Attribute placed on struct definitions.
+
+Creates a trait impl for each trait passed in as an argument.
+To do this, the trait must have a derive handler registered
+with `derive_via` beforehand. The traits in the stdlib that
+can be derived this way are `Eq`, `Ord`, `Default`, and `Hash`.
+
+Example:
+```rust
+#[derive(Eq, Default)]
+struct Foo<T> {
+    x: i32,
+    y: T,
+}
+
+fn main() {
+    let foo1 = Foo::default();
+    let foo2 = Foo { x: 0, y: &[0] };
+    assert_eq(foo1, foo2);
+}
+```
+
+### derive_via
+
+#include_code derive_via_signature noir_stdlib/src/meta/mod.nr rust
+
+Attribute placed on trait definitions.
+
+Registers a function to create impls for the given trait
+when the trait is used in a `derive` call. Users may use
+this to register their own functions to enable their traits
+to be derived by `derive`.
+
+Because this function requires a function as an argument which
+should produce a trait impl for any given struct, users may find
+it helpful to use a function like `std::meta::make_trait_impl` to
+help creating these impls.
+
+Example:
+```rust
+#[derive_via(derive_do_nothing)]
+trait DoNothing {
+    fn do_nothing(self);
+}
+
+comptime fn derive_do_nothing(s: StructDefinition) -> Quoted {
+    let typ = s.as_type();
+    quote {
+        impl DoNothing for $typ {
+            fn do_nothing(self) {
+                println("Nothing");
+            }
+        }
+    }
+}
+```
+
+As another example, `derive_eq` in the stdlib is used to derive the `Eq`
+trait for any struct. It makes use of `make_trait_impl` to do this:
+
+#include_code derive_eq noir_stdlib/src/cmp.nr rust
+
+### make_trait_impl
+
+#include_code make_trait_impl noir_stdlib/src/meta/mod.nr rust
+
+A helper function to more easily create trait impls while deriving traits.
+
+Note that this function only works for traits which:
+1. Have only one method
+2. Have no generics on the trait itself.
+  - E.g. Using this on a trait such as `trait Foo<T> { ... }` will result in the
+    generated impl incorrectly missing the `T` generic.
+
+If your trait fits these criteria then `make_trait_impl` is likely the easiest
+way to write your derive handler. The arguments are as follows:
+
+- `s`: The struct to make the impl for
+- `trait_name`: The name of the trait to derive. E.g. `quote { Eq }`.
+- `function_signature`: The signature of the trait method to derive. E.g. `fn eq(self, other: Self) -> bool`.
+- `for_each_field`: An operation to be performed on each field. E.g. `|name| quote { (self.$name == other.$name) }`.
+- `join_fields_with`: A separator to join each result of `for_each_field` with.
+  E.g. `quote { & }`. You can also use an empty `quote {}` for no separator.
+- `body`: The result of the field operations are passed into this function for any final processing.
+  This is the place to insert any setup/teardown code the trait requires. If the trait doesn't require
+  any such code, you can return the body as-is: `|body| body`.
+
+Example deriving `Hash`:
+
+#include_code derive_hash noir_stdlib/src/hash/mod.nr rust
+
+Example deriving `Ord`:
+
+#include_code derive_ord noir_stdlib/src/cmp.nr rust

docs/docs/noir/standard_library/meta/module.md

@@ -0,0 +1,27 @@
+---
+title: Module
+---
+
+`std::meta::module` contains methods on the built-in `Module` type which represents a module in the source program.
+Note that this type represents a module generally, it isn't limited to only `mod my_submodule { ... }`
+declarations in the source program.
+
+## Methods
+
+### name
+
+#include_code name noir_stdlib/src/meta/module.nr rust
+
+Returns the name of the module.
+
+### functions
+
+#include_code functions noir_stdlib/src/meta/module.nr rust
+
+Returns each function in the module.
+
+### is_contract
+
+#include_code is_contract noir_stdlib/src/meta/module.nr rust
+
+`true` if this module is a contract module (was declared via `contract foo { ... }`).