You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: lex.go
    path of file: ./repos/octant/vendor/github.com/BurntSushi/toml
    
    the code of the file until where you have to start completion: package toml

import (
	"fmt"
	"reflect"
	"runtime"
	"strings"
	"unicode"
	"unicode/utf8"
)

type itemType int

const (
	itemError itemType = iota
	itemNIL            // used in the parser to indicate no type
	itemEOF
	itemText
	itemString
	itemRawString
	itemMultilineString
	itemRawMultilineString
	itemBool
	itemInteger
	itemFloat
	itemDatetime
	itemArray // the start of an array
	itemArrayEnd
	itemTableStart
	itemTableEnd
	itemArrayTableStart
	itemArrayTableEnd
	itemKeyStart
	itemKeyEnd
	itemCommentStart
	itemInlineTableStart
	itemInlineTableEnd
)

const (
	eof              = 0
	comma            = ','
	tableStart       = '['
	tableEnd         = ']'
	arrayTableStart  = '['
	arrayTableEnd    = ']'
	tableSep         = '.'
	keySep           = '='
	arrayStart       = '['
	arrayEnd         = ']'
	commentStart     = '#'
	stringStart      = '"'
	stringEnd        = '"'
	rawStringStart
    
func lexValue(lx *lexer) stateFn {
	// We allow whitespace to precede a value, but NOT newlines.
	// In array syntax, the array states are responsible for ignoring newlines.
	r := lx.next()
	switch {
	case isWhitespace(r):
		return lexSkip(lx, lexValue)
	case isDigit(r):
		lx.backup() // avoid an extra state and use the same as above
		return lexNumberOrDateStart
	}
	switch r {
	case arrayStart:
		lx.ignore()
		lx.emit(itemArray)
		return lexArrayValue
	case inlineTableStart:
		lx.ignore()
		lx.emit(itemInlineTableStart)
		return lexInlineTableValue
	case stringStart:
		if lx.accept(stringStart) {
			if lx.accept(stringStart) {
				lx.ignore() // Ignore """
				return lexMultilineString
			}
			lx.backup()
		}
		lx.ignore() // ignore the '"'
		return lexString
	case rawStringStart:
		if lx.accept(rawStringStart) {
			if lx.accept(rawStringStart) {
				lx.ignore() // Ignore """
				return lexMultilineRawString
			}
			lx.backup()
		}
		lx.ignore() // ignore the "'"
		return lexRawString
	case '.': // special error case, be kind to users
		return lx.errorf("floats must start with a digit, not '.'")
	case 'i', 'n':
		if (lx.accept('n') && lx.accept('f')) || (lx.accept('a') && lx.accept('n')) {
			lx.emit(itemFloat)
			return lx.pop()
		}
	case '-', '+':
		return lexDecimalNumberStart
	}
	if unicode.IsLetter(r) {
		// Be permissive here; lexBool will give a nice error if the
		// user wrote something like
		//   x = foo
		// (i.e. not 'true' or 'false' but is something else word-like.)
		lx.backup()
		return lexBool
	}
	if r == eof {
		return lx.errorf("unexpected EOF; expected value")
	}
	return lx.errorf("expected value but found %q instead", r)
}