I came across a surprising book in the Needham Public Library when I was 15. It was called Starting Forth, and it was about a programming language called Forth.
The author Leo Brodie had written a charming and fun book about a very interesting language. Forth is a stack based language, and it has a postfix notation in its syntax. So instead of writing 3 + 4 you wrote 3 4 +. Seems strange, but to me it was very familiar because I got my start using HP calculators where you did exactly the same thing.
Forth is interactive, like BASIC. It has a very small core of functions called words, and you create an application by adding new words which have the same syntax as the ones that come built-in. Essentially you extend the language to solve your problem. Smalltalk is also like this.
Forth is the language used to program NASA's space shuttle, so it has some clout. I discovered that there are quite a few Forth fans out there, and I even managed to buy a Forth language cartridge for my VIC-20. Awesome.
Showing posts with label rpn. Show all posts
Showing posts with label rpn. Show all posts
Tuesday, October 13, 2009
Tuesday, April 17, 2007
Calculator or Computer?
I can remember it clearly the day I first was introduced to programming. When I was 11 or so years old I wandered into my father's home office and saw his calculator flashing patterns on its red LED display. I asked him what it was doing and he told me "You don't want to know." I told him, "Yes I do!"
The calculator in question was an HP-67. http://www.rskey.org/detail.asp?manufacturer=Hewlett-Packard&model=HP-67
My father was really wonderful about finding ways for me and my siblings to pursue things we were interested in. As long as my homework was done I could use his HP-67 in the dining room. The calculator came with a wonderful manual which taught programming in a most clear and enjoyable way. The HP-67 uses a Reverse Polish Notation style of arithmetic entry. It also supports a GOSUB and RETURN style of programming like BASIC. The other amazing feature of the HP-67 is a magnetic card reader. This is like a tiny floppy disk drive except that the card just moves straight through the calculator instead of spinning around. The cards are about a half inch in width. This made the HP-67 more of a personal computer than a calculator.
The calculator in question was an HP-67. http://www.rskey.org/detail.asp?manufacturer=Hewlett-Packard&model=HP-67
My father was really wonderful about finding ways for me and my siblings to pursue things we were interested in. As long as my homework was done I could use his HP-67 in the dining room. The calculator came with a wonderful manual which taught programming in a most clear and enjoyable way. The HP-67 uses a Reverse Polish Notation style of arithmetic entry. It also supports a GOSUB and RETURN style of programming like BASIC. The other amazing feature of the HP-67 is a magnetic card reader. This is like a tiny floppy disk drive except that the card just moves straight through the calculator instead of spinning around. The cards are about a half inch in width. This made the HP-67 more of a personal computer than a calculator.
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