diff options
Diffstat (limited to 'red.html.markdown')
| -rw-r--r-- | red.html.markdown | 77 |
1 files changed, 39 insertions, 38 deletions
diff --git a/red.html.markdown b/red.html.markdown index 05da3c3f..5f6ffc86 100644 --- a/red.html.markdown +++ b/red.html.markdown @@ -23,18 +23,19 @@ from any platform to any other platform. And it will do this all from a binary e Ready to learn your first Red? ``` -All text before the header will be treated as comment, as long as you avoid using the -word "red" starting with a capital "R" in this pre-header text. This is a temporary -shortcoming of the used lexer but most of the time you start your script or program -with the header itself. -The header of a red script is the capitalized word "red" followed by a -whitespace character followed by a block of square brackets []. -The block of brackets can be filled with useful information about this script or -program: the author's name, the filename, the version, the license, a summary of -what the program does or any other files it needs. -The red/System header is just like the red header, only saying "red/System" and -not "red". +All text before the header will be treated as comment, as long as you avoid +using the word "red" starting with a capital "R" in this pre-header text. +This is a temporary shortcoming of the used lexer but most of the time you +start your script or program with the header itself. +The header of a red script is the capitalized word "red" followed by a +whitespace character followed by a block of square brackets []. The block of +brackets can be filled with useful information about this script or program: +the author's name, the filename, the version, the license, a summary of what +the program does or any other files it needs. The red/System header is just +like the red header, only saying "red/System" and not "red". +``` +```red Red [] ;this is a commented line @@ -50,9 +51,9 @@ comment { ; no need to restrict this to a 'main' function. ; Valid variable names start with a letter and can contain numbers, -; variables containing only capital A thru F and numbers and ending with 'h' are -; forbidden, because that is how hexadecimal numbers are expressed in Red and -; Red/System. +; variables containing only capital A thru F and numbers and ending with 'h' +; are forbidden, because that is how hexadecimal numbers are expressed in Red +; and Red/System. ; assign a value to a variable using a colon ":" my-name: "Red" @@ -63,8 +64,8 @@ reason-for-using-the-colon: {Assigning values using the colon makes } is-this-name-valid?: true -; print output using print, or prin for printing without a newline or linefeed at the -; end of the printed text. +; print output using print, or prin for printing without a newline or linefeed +; at the end of the printed text. prin " My name is " print my-name My name is Red @@ -72,7 +73,7 @@ My name is Red print ["My name is " my-name lf] My name is Red -; In case you haven't already noticed: statements do NOT end with a semicolon ;-) +; If you haven't already noticed: statements do NOT end with a semicolon ;-) ; ; Datatypes @@ -85,13 +86,13 @@ My name is Red ; Some of the available types are integer! string! block! ; Declaring variables before using them? -; Red knows by itself what variable is best to use for the data you want to use it -; for. +; Red knows by itself what variable is best to use for the data you want to +; use it for. ; A variable declaration is not always necessary. ; It is considered good coding practise to declare your variables, ; but it is not forced upon you by Red. -; You can declare a variable and specify its type. a variable's type determines its -; size in bytes. +; You can declare a variable and specify its type. a variable's type +; determines its size in bytes. ; Variables of integer! type are usually 4 bytes or 32 bits my-integer: 0 @@ -111,10 +112,10 @@ i2 - i1 ; result 1 i2 * i1 ; result 2 i1 / i2 ; result 0 (0.5, but truncated towards 0) -; Comparison operators are probably familiar, and unlike in other languages you -; only need a single '=' sign for comparison. -; There is a boolean like type in Red. It has values true and false, but also the -; values on/off or yes/no can be used +; Comparison operators are probably familiar, and unlike in other languages +; you only need a single '=' sign for comparison. +; There is a boolean like type in Red. It has values true and false, but also +; the values on/off or yes/no can be used 3 = 2 ; result false 3 != 2 ; result true @@ -127,22 +128,22 @@ i1 / i2 ; result 0 (0.5, but truncated towards 0) ; Control Structures ; ; if -; Evaluate a block of code if a given condition is true. IF does not return any value, -; so cannot be used in an expression. +; Evaluate a block of code if a given condition is true. IF does not return +; any value, so cannot be used in an expression. if a < 0 [print "a is negative"] ; either -; Evaluate a block of code if a given condition is true, else evaluate an alternative -; block of code. If the last expressions in both blocks have the same type, EITHER can -; be used inside an expression. -either a < 0 [ +; Evaluate a block of code if a given condition is true, else evaluate an +; alternative block of code. If the last expressions in both blocks have the +; same type, EITHER can be used inside an expression. +either a > 0 [ + msg: "positive" +][ either a = 0 [ msg: "zero" ][ msg: "negative" ] -][ - msg: "positive" ] print ["a is " msg lf] @@ -150,14 +151,14 @@ print ["a is " msg lf] ; There is an alternative way to write this ; (Which is allowed because all code paths return a value of the same type): -msg: either a < 0 [ +msg: either a > 0 [ + "positive" +][ either a = 0 [ "zero" ][ "negative" ] - ][ - "positive" ] print ["a is " msg lf] @@ -172,8 +173,8 @@ until [ ] ; will output: ooooo -; Note that the loop will always be evaluated at least once, even if the condition is -; not met from the beginning. +; Note that the loop will always be evaluated at least once, even if the +; condition is not met from the beginning. ; while ; While a given condition is met, evaluate a block of code. |