func literalToken(literal uint32) token { return token(literalType + literal) }

// Convert a < xlength, xoffset > pair into a match token.
func matchToken(xlength uint32, xoffset uint32) token {
	return token(matchType + xlength<<lengthShift + xoffset)
}

// Returns the literal of a literal token.
func (t token) literal() uint32 { return uint32(t - literalType) }

// Returns the extra offset of a match token.

They consist of the type of the literal followed by a brace-bound list of elements.
Each element may optionally be preceded by a corresponding key.
</p>

<pre class="ebnf">
CompositeLit  = LiteralType LiteralValue .
LiteralType   = StructType | ArrayType | "[" "..." "]" ElementType |
                SliceType | MapType | TypeName .
LiteralValue  = "{" [ ElementList [ "," ] ] "}" .
ElementList   = KeyedElement { "," KeyedElement } .

They consist of the type of the literal followed by a brace-bound list of elements.
Each element may optionally be preceded by a corresponding key.
</p>

<pre class="ebnf">
CompositeLit  = LiteralType LiteralValue .
LiteralType   = StructType | ArrayType | "[" "..." "]" ElementType |
                SliceType | MapType | TypeName [ TypeArgs ] .
LiteralValue  = "{" [ ElementList [ "," ] ] "}" .