Editing BASIC-PLUS (section)

{{Short description|Dialect of the BASIC Programming Language used on the RSTS/E Operating System on PDP-11 computers}}
{{Infobox programming language
| name = BASIC-PLUS
| paradigm = [[imperative programming|imperative]]
| year = {{start date and age|1970}}
| influenced_by = [[Dartmouth BASIC]], [[Tymshare SUPER BASIC]]
| influenced = [[Microsoft BASIC]]
| operating_system = [[RSTS/E]]
| status = Discontinued
}}
'''BASIC-PLUS''' is an extended dialect of the [[BASIC]] [[programming language]] that was developed by [[Digital Equipment Corporation]] (DEC) for use on its [[RSTS/E]] time-sharing operating system for the [[PDP-11]] series of 16-bit [[minicomputer]]s in the early 1970s through the 1980s.

BASIC-PLUS was based on BASIC-8 for the [[TSS/8]],<ref name="computer-engineering">{{cite book |last1=Bell |first1=C. Gordon |url=http://bitsavers.org/pdf/dec/_Books/Bell-ComputerEngineering.pdf |title=Computer Engineering: A DEC View of Hardware Systems Design |last2=Mudge |first2=J. Craig |last3=McNamara |first3=John N. |publisher=[[Digital Press]] |year=1978 |isbn=0-932376-00-2 |authorlink1=Gordon Bell}}</ref> itself based very closely on the original [[Dartmouth BASIC]]. BASIC-PLUS added a number of new structures, as well as features from [[JOSS]] concerning conditional statements and formatting. In turn, BASIC-PLUS was the version on which the original [[Microsoft BASIC]] was patterned.<ref name=manes>{{cite book |title= Gates |first=Stephen |last=Manes |page=61 |publisher=Doubleday |date=1993 |isbn=9780385420754 |url=https://books.google.com/books?id=KBtPAAAAMAAJ}}</ref>

Notable among the additions made to BASIC-PLUS was the introduction of string functions like {{mono|MID$}} and {{mono|LEFT$}}, in addition to Dartmouth's original all-purpose {{mono|CHANGE}} command. In future versions of the language, notably Microsoft's, {{mono|CHANGE}} was removed and BASIC-PLUS's string functions became the only ways to perform these sorts of operations. Most BASICs to this day follow this convention.

The language was later rewritten as a true [[compiler]] as '''BASIC-Plus-2''', and was ported to the [[VAX-11]] platform as that machine's native BASIC implementation. This version survived several platform changes, and is today known as [[VSI BASIC for OpenVMS]].