Oracle Tutoring, Campbell River, BC
(250) 203-6544 (text) or (250) 830-0295 (talk)
Self-tutoring about LISP: the tutor mentions how to check if a variable if defined without invoking an error. Let’s imagine, in LISP, you want to check if x is defined. (boundp ‘x) T if it is, NIL if not:) Source: …
Comp Sci: LISP: how to check if a variable is defined Read more »
Self-tutoring about comp-sci: the tutor mentions Perl’s reaction to if(var), var undefined. In yesterday’s post I mention about LISP and its reaction to a few “if” situations. In particular, LISP won’t tolerate being asked “if” about an undefined variable. LISP, …
Self-tutoring about Comp Sci: the tutor mentions true and false in LISP. An interesting aspect of every computer language is what it thinks of as “true” vs “false”. Many languages think 0 is false, while any other declared value, such …
Computer science: LISP: ideas about true and false Read more »
Self-tutoring about awk: the tutor mentions the if(var) condition. Some computer languages allow if(x) as a condition; others insist an explicit comparison, such as if(x!=0). In my experience, awk allows if(x).
Self-tutoring about Perl regular expressions: the tutor makes an observation. Perl has the interesting character class \h that signifies “horizontal whitespace.” It can be very useful to capture a word in a sentence. Suppose, for instance, you want to capture …
Self-tutoring about regular expressions with JavaScript: the tutor mentions the idea of the boundary condition. In JavaScript regex, a boundary condition can mean a whitespace or punctuation before or after a word. That’s my understanding, anyway. Source: developer.mozilla.org
Self-tutoring about comp sci terminology: the tutor looks into a point of usage. Apparently one spoken way to indicate “-” (dash, hyphen, minus, or whatever you call it) is “tack.” I encountered this today: apparently it’s common in some circles. …
Self-tutoring about using Visual Studio 2019 with .net Core: the tutor mentions a problem he ran into and what fixed it. I tried scaffolding but it wasn’t working. Then I made a new project. This time, on the “Create a …
Self-tutoring about regular expressions: the tutor mentions a possible misstep. It’s true that, typically, in regex, ^ means beginning and $ means end – particularly outside of []. Consider the string s1: “Hello there Smedley!” The pattern ^there$ won’t find …
Self-tutoring about PHP: the tutor mentions an idea about PHP global. Consider the file $var1=”hello”; function f1(){ echo $var1; } f1(); //call f1 In the code above, with almost any programming language I know of, $var1 has value “hello” in …