ECMA-55 is an interesting standard. It explains a lot of what we saw that was common across the different dialects of BASIC. If you were using BASIC in those days, you’ll no doubt remember that every version of BASIC was different and you had to choose which flavour of BASIC to write for each time. Whenever a new BASIC compiler or interpreter was released, it would differ in some way from all of its predecessors. The positive to that was “bigger and better”. The negative was, your old programs wouldn’t run. ECMA-55 was the missing link (for me at the time) that explained what the essence of BASIC actually was.<\/p>\n
It wasn’t closely followed as many had slight variations to core functionality and many added things to the core; but it does show what they were all hovering around. It is a good read and is fairly short.<\/p>\n
A Standards Compliant BASIC Interpreter<\/h2>\n
John mentions on the sourceforge page that there is a recent implementation of the as-defined language in bas55<\/a>. That one is neat, compact and comprehensive. The executable is only 75 KB which is very good.<\/p>\n If you look through the source code for bas55, you’ll see that it used Bison or a later derivative to translate the BASIC grammar into a series of tables that the program then uses. It is a good approach and tools like that result in significant savings in development time and also produce fast compilers \/ interpreters. For John’s purposes, he wanted to avoid teaching additional tools and allow his students to focus on how simple compilers work. Both approaches have their merits.<\/p>\n I wanted something that came close to the standard; but would be fairly easily extended.<\/p>\n I wanted both the simplicity and development speed of a tool generated grammar recogniser; but also the simplicity of “pure code” so I could see what was being done, instead of just staring dumbly at a page of state \/ transition numbers.<\/p>\n After about two weeks of pretty busy evenings and weekends, I am pleased to provide another (mostly) ECMA-55 compliant BASIC interpreter. My grammar code is less efficient that Jorge’s bas55 so my executable is 120 KB. It’s probably also slower but it should serve as a good starting point for adding features. It’s not perfect but I think you’ll like it. It does have some additions already; such as: TRON \/ TROFF and a simple immediate mode (? expr) so you can try things out whilst thinking through the next line of code. I also like how smoothly the HELP system turned out.<\/p>\n You can download a copy of basic1<\/a>. It is free to use and doesn’t have any time limits on it. Whilst my executable is 120 KB, the download includes the help file too and so, as a single ZIP file, the download is only 40 KB in total!<\/p>\n It is version 0.00 for now. You should see the version number go up over the next few weeks as I add things. It does already have the ability to load and run a BASIC program directly from the OS prompt (see HELP STARTUP).<\/p>\n *** Update 10 Jun 2018 *** *** Update 03 Jun 2018 *** This is part of the CP\/M topic<\/a>. I’ve recently been looking at BASIC for Windows. What I wanted was something that captured the simplicity of CP\/M or early MSDOS days, was small in size and had a reasonably useful set of functionality. TinyBASIC was a fairly good compromise but it lacked a few things …<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[16,59],"tags":[],"_links":{"self":[{"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/posts\/2157"}],"collection":[{"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/comments?post=2157"}],"version-history":[{"count":7,"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/posts\/2157\/revisions"}],"predecessor-version":[{"id":2186,"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/posts\/2157\/revisions\/2186"}],"wp:attachment":[{"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/media?parent=2157"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/categories?post=2157"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sydneysmith.com\/wordpress\/wp-json\/wp\/v2\/tags?post=2157"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Basic1<\/h2>\n
![\"\"](\"http:\/\/www.sydneysmith.com\/wordpress\/wp-content\/uploads\/2018\/05\/basic1-300x203.png\")
<\/a><\/p>\n
\nBasic1 version 0.02<\/a> has been done. This corrects a few more things and adds most of the functions that were prevalent in the late 1970s and early 1980s. It now successfully runs a number of programs from that era with minimal tweaks. See HELP CHANGES for more info. <\/p>\n
\nBasic1 version 0.01<\/a> has been done. This makes variable names case-insensitive and corrects the grammar to make subtraction left-to-right associative (10-2-1 now =7, like it should). There are a number of other additions, see HELP CHANGES for more info. <\/p>\n
\nSee the Basic1<\/a> page for the latest and other versions.<\/p>\n","protected":false},"excerpt":{"rendered":"