View source for DOPE (Dartmouth Oversimplified Programming Experiment)

{{Short description|Introductory programming language prior to BASIC (1962)}}
{{Infobox programming language
| name = DOPE (Dartmouth Oversimplified Programming Experiment)
| logo = <!-- Filename only -->
| logo caption = 
| screenshot = <!-- Filename only -->
| screenshot caption = 
| paradigms = [[Procedural programming|procedural]]
| family = 
| designers = [[Biography:John G. Kemeny|John G. Kemeny]]
| developer = Sidney Marshall
| released = {{Start date and age|1962}}<!-- If known, add |mm|dd -->
| latest release version = 
| latest release date = <!-- {{Start date and age|198?|mm|dd|df=yes}} -->
| typing = 
| scope = 
| programming language = [[Assembly language|Assembly]]
| discontinued = Yes
| platform = LGP-30
| operating system = <!-- The LGP used no operating system. -->
| license = 
| file ext = 
| file format = <!-- or: | file formats = -->
| website = <!-- {{URL|www.example.com}} -->
| implementations = 
| dialects = 
| influenced by = [[DARSIMCO]], DART, [[Dartmouth ALGOL 30]], [[Fortran]]
| influenced = [[Dartmouth BASIC]]
}}
'''DOPE''', short for '''Dartmouth Oversimplified Programming Experiment''', was a simple [[Programming language|programming language]] designed by [[Biography:John G. Kemeny|John Kemény]] in 1962 to offer students a transition from [[Flowchart|flow-charting]] to programming the LGP-30. Lessons learned from implementing DOPE were subsequently applied to the invention and development of [[Dartmouth BASIC|BASIC]].<ref>{{cite encyclopedia
|encyclopedia=History of programming languages I
|first=Thomas
|last=Kurtz
|pages=517-518 [https://archive.org/details/historyofprogram0000hist/page/517 517–518]
|publisher=ACM
|date=1981
|isbn=0-12-745040-8
|doi=10.1145/800025.1198404
|chapter-url=https://dl.acm.org/citation.cfm?doid=800025.1198404
|chapter=BASIC
|title=History of programming languages
|url=https://archive.org/details/historyofprogram0000hist/page/517
}}</ref>

==Description==
Each statement was designed to correspond to a flowchart operation and consisted of a numeric line number, an operation, and the required operands:
  7 + A B C
 10 SIN X Z

The final variable specified the destination for the computation. The above program corresponds in functionality to the later BASIC program:
{{sxhl|2=cbmbas|1=<nowiki/>
 7 LET C=A+B
10 LET Z=SIN(X)
}}
DOPE might be the first programming language to require every statement to have a [[Line number|line number]], predating [[JOSS]] and BASIC.

The language was case insensitive.

Variable names were a single letter A to Z, or a letter followed by a digit (A0 to Z9). As with [[Fortran]], different letters represented different variable types. Variables starting with letters A to D were floating point, as were variables from I to Z; variables E, F, G, and H each were defined as vectors with components from 1 to 16.

{| class="wikitable"
|+ Caption text
|-
! Operation !! Function !! Number of operands
|-
| A || Ask (prompt for input) || 2
|-
| C || [[Arithmetic IF]] || 4
|-
| E || End loop || (Unknown)
|-
| J || Input into variable || 1
|-
| N || Print a newline || (Unknown)
|-
| P || Print a variable || 1
|-
| T || Jump || 1
|-
| Z || For loop || (Unknown)
|-
| + || Addition || 3
|-
| - || Subtraction || 3
|-
| * || Multiplication || 3
|-
| / || Division || 3
|-
| EXP || E to the power || 2
|-
| LOG || [[Logarithm]] || 2
|-
| SIN || [[Sine]] || 2
|-
| SQR || [[Square root]] || 2
|}

The language was used by only one freshman computing class.<ref>{{cite book |last1=Williams |first1=Michael |title=A History of Computing Technology |date=November 1, 1985 |publisher=Prentice-Hall |isbn=0133899179 |pages=432 |edition=1st}}</ref> Kemeny collaborated with high school student Sidney Marshall (taking freshman calculus) to develop the language.<ref>''Application to the National Science Foundation'', Kurtz, Rieser, and Meck, cited in Rankin, pages 20-21</ref><ref>Kemeny, John G.; Kurtz, Thomas E. (1985). ''Back To BASIC:  The History, Corruption, and Future of the Language''. Addison-Wesley Publishing Company, Inc. 141&nbsp;pp.&nbsp;{{ISBN|0-201-13433-0}}</ref>

==Legacy==
According to [[Biography:Thomas E. Kurtz|Thomas Kurtz]], a co-inventor of BASIC, "Though not a success in itself, DOPE presaged BASIC. DOPE provided default vectors, default printing formats, and general input formats. Line numbers doubled as jump targets."

The language had a number of other features and innovations that were carried over into BASIC:
# Variable names were either a letter or a letter followed by a digit
# Arrays (vectors) did not have to be declared and had a default size (16 instead of 10)
# Every line required a numeric label*
# Lines were sorted in numeric order*
# Every line begin with a keyword*
# Function names were three letters long*
# The only loop construct was a for-loop
{{asterisk}}Unlike either [[Fortran]] or Algol 60.

==See also==
* [[DARSIMCO]], 'Dartmouth Simplified Code', a 1956 assembler macro language
* [[Dartmouth ALGOL 30]], a compiler developed by Dartmouth for the LGP-30

==References==
{{Reflist}}

[[Category:Programming languages]]



{{Sourceattribution|DOPE (Dartmouth Oversimplified Programming Experiment)|1}}