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Module std::type_name

Functionality for converting Move types into values. Use with care!

use std::address;
use std::ascii;
use std::option;
use std::vector;

Struct TypeName

public struct TypeName has copy, drop, store
Fields
name: std::ascii::String
String representation of the type. All types are represented using their source syntax: "u8", "u64", "bool", "address", "vector", and so on for primitive types. Struct types are represented as fully qualified type names; e.g. 00000000000000000000000000000001::string::String or 0000000000000000000000000000000a::module_name1::type_name1<0000000000000000000000000000000a::module_name2::type_name2<u64>> Addresses are hex-encoded lowercase values of length ADDRESS_LENGTH (16, 20, or 32 depending on the Move platform)

Constants

ASCII Character code for the : (colon) symbol.

const ASCII_COLON: u8 = 58;

ASCII Character code for the v (lowercase v) symbol.

const ASCII_V: u8 = 118;

ASCII Character code for the e (lowercase e) symbol.

const ASCII_E: u8 = 101;

ASCII Character code for the c (lowercase c) symbol.

const ASCII_C: u8 = 99;

ASCII Character code for the t (lowercase t) symbol.

const ASCII_T: u8 = 116;

ASCII Character code for the o (lowercase o) symbol.

const ASCII_O: u8 = 111;

ASCII Character code for the r (lowercase r) symbol.

const ASCII_R: u8 = 114;

The type is not from a package/module. It is a primitive type.

const ENonModuleType: u64 = 0;

Function with_defining_ids

Return a value representation of the type T. Package IDs that appear in fully qualified type names in the output from this function are defining IDs (the ID of the package in storage that first introduced the type).

public fun with_defining_ids<T>(): std::type_name::TypeName
Implementation 
public native fun with_defining_ids<T>(): TypeName;

Function with_original_ids

Return a value representation of the type T. Package IDs that appear in fully qualified type names in the output from this function are original IDs (the ID of the first version of the package, even if the type in question was introduced in a later upgrade).

public fun with_original_ids<T>(): std::type_name::TypeName
Implementation 
public native fun with_original_ids<T>(): TypeName;

Function defining_id

Like with_defining_ids, this accesses the package ID that original defined the type T.

public fun defining_id<T>(): address
Implementation 
public native fun defining_id<T>(): address;

Function original_id

Like with_original_ids, this accesses the original ID of the package that defines type T, even if the type was introduced in a later version of the package.

public fun original_id<T>(): address
Implementation 
public native fun original_id<T>(): address;

Function is_primitive

Returns true iff the TypeName represents a primitive type, i.e. one of u8, u16, u32, u64, u128, u256, bool, address, vector.

public fun is_primitive(self: &std::type_name::TypeName): bool
Implementation 
public fun is_primitive(self: &TypeName): bool {
    let bytes = self.name.as_bytes();
    bytes == &b"bool" ||
        bytes == &b"u8" ||
        bytes == &b"u16" ||
        bytes == &b"u32" ||
        bytes == &b"u64" ||
        bytes == &b"u128" ||
        bytes == &b"u256" ||
        bytes == &b"address" ||
        (
            bytes.length() >= 6 &&
            bytes[0] == ASCII_V &&
            bytes[1] == ASCII_E &&
            bytes[2] == ASCII_C &&
            bytes[3] == ASCII_T &&
            bytes[4] == ASCII_O &&
            bytes[5] == ASCII_R,
        )
}

Function as_string

Get the String representation of self

public fun as_string(self: &std::type_name::TypeName): &std::ascii::String
Implementation 
public fun as_string(self: &TypeName): &String {
    &self.name
}

Function address_string

Get Address string (Base16 encoded), first part of the TypeName. Aborts if given a primitive type.

public fun address_string(self: &std::type_name::TypeName): std::ascii::String
Implementation 
public fun address_string(self: &TypeName): String {
    assert!(!self.is_primitive(), ENonModuleType);
    // Base16 (string) representation of an address has 2 symbols per byte.
    let len = address::length() * 2;
    let str_bytes = self.name.as_bytes();
    let mut addr_bytes = vector[];
    let mut i = 0;
    // Read `len` bytes from the type name and push them to addr_bytes.
    while (i < len) {
        addr_bytes.push_back(str_bytes[i]);
        i = i + 1;
    };
    ascii::string(addr_bytes)
}

Function module_string

Get name of the module. Aborts if given a primitive type.

public fun module_string(self: &std::type_name::TypeName): std::ascii::String
Implementation 
public fun module_string(self: &TypeName): String {
    assert!(!self.is_primitive(), ENonModuleType);
    // Starts after address and a double colon: `<addr as HEX>::`
    let mut i = address::length() * 2 + 2;
    let str_bytes = self.name.as_bytes();
    let mut module_name = vector[];
    let colon = ASCII_COLON;
    loop {
        let char = &str_bytes[i];
        if (char != &colon) {
            module_name.push_back(*char);
            i = i + 1;
        } else {
            break
        }
    };
    ascii::string(module_name)
}

Function into_string

Convert self into its inner String

public fun into_string(self: std::type_name::TypeName): std::ascii::String
Implementation 
public fun into_string(self: TypeName): String {
    self.name
}

Function get

public fun get<T>(): std::type_name::TypeName
Implementation 
public fun get<T>(): TypeName {
    with_defining_ids<T>()
}

Function get_with_original_ids

public fun get_with_original_ids<T>(): std::type_name::TypeName
Implementation 
public fun get_with_original_ids<T>(): TypeName {
    with_original_ids<T>()
}

Function borrow_string

public fun borrow_string(self: &std::type_name::TypeName): &std::ascii::String
Implementation 
public fun borrow_string(self: &TypeName): &String {
    self.as_string()
}

Function get_address

public fun get_address(self: &std::type_name::TypeName): std::ascii::String
Implementation 
public fun get_address(self: &TypeName): String {
    self.address_string()
}

Function get_module

public fun get_module(self: &std::type_name::TypeName): std::ascii::String
Implementation 
public fun get_module(self: &TypeName): String {
    self.module_string()
}