| Type: | Package |
| Title: | 1970s BASIC Interpreter |
| Version: | 1.0.2 |
| Date: | 2022-10-24 |
| Author: | Mike Lee |
| Maintainer: | Mike Lee <random.deviate@gmail.com> |
| Description: | Executes BASIC programs from the 1970s, for historical and educational purposes. This enables famous examples of early machine learning, artificial intelligence, natural language processing, cellular automata, and so on, to be run in their original form. |
| License: | GPL-3 |
| Depends: | R (≥ 3.3.0) |
| NeedsCompilation: | no |
| Packaged: | 2022-10-24 01:16:01 UTC; Mike |
| Repository: | CRAN |
| Date/Publication: | 2022-10-24 06:15:06 UTC |
BASIC Interpreter
Description
Runs 1970s BASIC programs.
Details
Interprets and executes a subset of early (1975) Altair/Microsoft BASIC, plus some generalisations and extensions. Enables various programs of historical interest to be run in their primal form. A selection of public-domain examples are included.
Author(s)
Mike Lee
See Also
Examples
require(brassica)
## Not run:
# Load and run the 'Wumpus' program.
RUN("WUMPUS")
## End(Not run)
List BASIC Programs
Description
Lists whichever BASIC program is loaded.
Usage
LIST()
Value
Returns a character vector, containing the complete listing of whichever BASIC program is in memory at the time.
See Also
Examples
# List the current BASIC program.
LIST()
Convert to Lower Case
Description
Converts a BASIC program to lower case, except for any string literals.
Usage
LowerCode(p)
Arguments
p |
A BASIC program listing, as a character vector. |
Value
Returns the converted listing, as a character vector.
See Also
Examples
# Convert a program to lower case.
LowerCode(c('10 LET X=X+1', '20 PRINT "Hello, World!"'))
Check BASIC Programs
Description
Returns a data frame of any BASIC program lines that contain one or
more unexecuted statements.
Used with repeated calls of RUN(), this provides a test of code syntax
and accessibility.
Usage
NotRun(pretty = TRUE)
Arguments
pretty |
A single logical value.
If |
Value
Returns a data frame of any lines, from the currently-loaded BASIC program, containing one or more unexecuted statements. Lines are listed with both their BASIC line numbers and the corresponding file line numbers of the source script. A persistent appearance here may, but does not necessarily, signify a problem with the line.
Note
BASIC ON and IF-THEN-ELSE statements contain multiple
alternative clauses.
Each such statement, as a whole, is marked as having been executed once any one
of its clauses has been run without error.
Hence, the absence of such a statement from the NotRun() frame does not
guarantee that all of its clauses are error-free.
See Also
Examples
# Peruse which lines have not yet been run.
NotRun()
Run BASIC Programs
Description
Loads and runs BASIC programs.
Usage
RUN(program = NULL, ttx = 0, tty = 0, up = FALSE)
Arguments
program |
A character string, containing the name or file path of a BASIC program. Omitting this re-runs the currently-loaded program. |
ttx |
Aesthetic teletype option. A delay, of not more than 200 milliseconds, to be applied after printing each character. In practice, the actual delay will be this time plus however long it takes to flush the console, plus interpreter overheads. Depending on the model, a real teletype could manage around ten characters per second. Making this negative imposes no delay, but flushes the console after each completed line (not after each character). |
tty |
Aesthetic teletype option. A delay, of not more than 2000 milliseconds, to be applied after each line of printing. Making this negative imposes no delay, but still flushes the console after each completed line. |
up |
Aesthetic teletype option.
Making this |
Details
List of bundled example programs (from the references):
| Animal | by Arthur Luehrmann | (decision trees) |
| Camel | by the Heath Users Group | (random walk) |
| Chase | by Mac Oglesby | (robots) |
| Eliza | by Jeff Shrager | (language processing) |
| Even Wins | by Eric Peters | (machine learning) |
| Flip | by John S. James | (machine learning) |
| Four in a Row | by James L. Murphy | (artificial intelligence) |
| Guess-It | by Gerard Kierman | (bluffing) |
| Hammurabi | by David H. Ahl | (resource management) |
| Hexapawn | by R. A. Kaapke | (machine learning) |
| Inkblot | by Scott Costello | (projection) |
| Life | by Clark Baker | (cellular automata) |
| Maze | by Richard Schaal | (depth-first search) |
| Not One | by Robert Puopolo | (expectation values) |
| Sea Battle | by Vincent Erickson | (monsters) |
| Super Star Trek | by Richard Leedon | (vector space) |
| Wumpus | by Gregory Yob | (graph topology) |
All of these are in the public domain.
Value
Returns an invisible NULL, after printing to standard output.
Note
Many BASIC programs ask for user input after printing a custom prompt.
When ttx is greater than zero, some R sessions may incorrectly position
the cursor at the beginning of the line, or on the next.
Neither occurrence is fatal.
Known to be affected: Windows R terminal (‘R’ and ‘Rterm’, but the
‘Rgui’ console is fine), Mac R console (but the Bash terminal is fine),
RStudio.
Additionally, double buffering, or the like, may interfere with the effect at
higher speeds (Mac R console, again).
References
David H. Ahl & Steve North, BASIC Computer Games (1978)
David H. Ahl & Steve North, More BASIC Computer Games (1979)
See Also
Examples
## Not run:
# Load and run 'Wumpus'.
RUN("wumpus")
# Load and run 'Chase', flushing the
# console after every line of output.
RUN("chase", -1)
# Load and run 'Camel', with full
# retro-style teletypewriter effects.
RUN("camel", 20, 300, TRUE)
# Load and run your program.
RUN("myprogram.bas")
# Re-run the last program
# (without re-loading it).
RUN()
## End(Not run)
Convert to Upper Case
Description
Converts a BASIC program to upper case, except for any string literals.
Usage
UpperCode(p)
Arguments
p |
A BASIC program listing, as a character vector. |
Value
Returns the converted listing, as a character vector.
See Also
Examples
# Convert a program to upper case.
UpperCode(c('10 let x=x+1', '20 print "Hello, World!"'))