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Module 0x1::type_name

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

use 0x1::ascii;

Struct TypeName​

struct TypeName has copy, drop, store
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Fields
name: 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 c (lowercase c) symbol.

const ASCII_C: u8 = 99;

ASCII Character code for the : (colon) symbol.

const ASCII_COLON: u8 = 58;

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

const ASCII_E: u8 = 101;

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;

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

const ASCII_T: u8 = 116;

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

const ASCII_V: u8 = 118;

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

const ENonModuleType: u64 = 0;

Function get​

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

Function get_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 get_with_original_ids<T>(): type_name::TypeName
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Implementation
public native fun get_with_original_ids<T>(): TypeName;

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: &type_name::TypeName): bool
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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 borrow_string​

Get the String representation of self

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

Function get_address​

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

public fun get_address(self: &type_name::TypeName): ascii::String
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Implementation
public fun get_address(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 get_module​

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

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