bmx-site/docs/api/brl/brl_retro.md

---

id: brl.retro title: BRL.Retro

sidebar_label: BRL.Retro

The BASIC compatibility module provides miscellaneous functions that emulate the behaviour of 'classic' BASIC.

The functions in this module have largely been superceded by BlitzMax features such as 'string slicing', and the Find, Replace, Trim, ToLower and ToUpper string methods.

However, for programmers from a classic BASIC background, these utility functions should make the transition to BlitzMax a little easier.

NOTE: Strings in classic BASIC are '1 based'. This means that the first character within a string is at index 1, the second at index 2 and so on. However, BlitzMax strings are '0 based', meaning the first character is at index 0, the second at index 1 and so on. The instr and Mid functions in this module retain the '1 based' behaviour of classic BASIC.

Functions

Function Mid$( str$,pos,size=-1 )

Extract substring from a string

The Mid$ command returns a substring of a String.

Given an existing string, a position from the start of the string and an optional size, Mid creates a new string equal to the section specified. If no size if given, Mid returns the characters in the existing string from position to the end of the string.

For compatibility with classic BASIC, the pos parameter is 'one based'.

Returns

A sequence of characters from str starting at position pos and of length size

Function Instr( str$,sub$,start=1 )

Find a string within a string

The start parameter allows you to specifying a starting index for the search.

For compatiblity with classic BASIC, the start parameter and returned position are both 'one based'.

Returns

The position within str of the first matching occurance of sub

Function Left$( str$,n )

Extract characters from the beginning of a string

The Left$ command returns a substring of a String. Given an existing String and a size, Left$ returns the first size characters from the start of the String in a new String.

Returns

size leftmost characers of str

Function Right$( str$,n )

Extract characters from the end of a string

The Right$ command returns a substring of a String. Given an existing String and a size, Right$ returns the last size characters from the end of the String.

Returns

size rightmost characters of str

Function LSet$( str$,n )

Left justify string

Returns

A string of length n, padded with spaces

Function RSet$( str$,n )

Right justify string

Returns

A string of length n, padded with spaces

Function Replace$( str$,sub$,replaceWith$ )

Performs a search and replace function

The Replace$ command replaces all instances of one string with another.

Returns

A string with all instances of sub$ replaced by replace$

Function Trim$( str$ )

Remove unprintable characters from ends a string

Returns

str with leading and trailing unprintable characters removed

Function Lower$( str$ )

Convert string to lowercase

Returns

Lowercase equivalent of str

Function Upper$( str$ )

Convert string to uppercase

Returns

Uppercase equivalent of str

Function Hex$( val )

Convert an integer value to a hexadecimal string

Returns

The hexadecimal string representation of val

Function Bin$( val )

Convert an integer value to a binary string

Returns

The binary string representation of val

Function LongHex$( val:Long )

Convert a 64 bit long integer value to a hexadecimal string

Returns

The hexadecimal string representation of val

Function LongBin$( val:Long )

Convert a 64 bit long integer value to a binary string

Returns

The binary string representation of val