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Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 98 |
1 files changed, 56 insertions, 42 deletions
@@ -13,14 +13,15 @@ God help you if you want to use this for anything. ### Procedures -Custom procedures can be created before the main body of the program: +Code is separated into procedures. A program must define a procedure named `MAIN` to serve as the entrypoint. ``` PROC is-even? 2 OVER % 0 == END -4 is-even? . '''true''' -5 is-even? . '''false''' -PROC illegal "this is an error" . END ''' not allowed, defined after body program body ''' +PROC MAIN + 4 is-even? . '''true''' + 5 is-even? . '''false''' +END ``` ### Postfix/Reverse Polish notation @@ -28,24 +29,25 @@ PROC illegal "this is an error" . END ''' not allowed, defined after body progra Procedures are invoked by pushing its arguments to the stack in reverse order and then calling the procedure: ``` -''' compute 2+1 and print the result (3) ''' -1 2 + . - -''' compute 2-1 and print the result (1) ''' -1 2 - . - -''' compute 1-2 and print the result (-1) ''' -2 1 - . - -''' test if 5 is greater than 6 and print the result (false) ''' -6 5 > . - -''' compute 2+3, test if 3 is less than the sum, and print the result ''' -3 2 + 3 < . - -''' concatenate two strings and print the result ''' -" but backwards" "it's like LISP" ++ . - +PROC + ''' compute 2+1 and print the result (3) ''' + 1 2 + . + + ''' compute 2-1 and print the result (1) ''' + 1 2 - . + + ''' compute 1-2 and print the result (-1) ''' + 2 1 - . + + ''' test if 5 is greater than 6 and print the result (false) ''' + 6 5 > . + + ''' compute 2+3, test if 3 is less than the sum, and print the result ''' + 3 2 + 3 < . + + ''' concatenate two strings and print the result ''' + " but backwards" "it's like LISP" ++ . +END ``` ### Comments @@ -53,14 +55,16 @@ Procedures are invoked by pushing its arguments to the stack in reverse order an Comments are multi-line only and are opened and closed with three single-quotes: ``` -IF 2 9 % 0 == DO - ''' TODO: come up with a better message to print - maybe something to do with the mod result being 0? ''' - "true branch" -ELSE - ''' i feel like we could mention that the number is odd? or something? ''' - "false branch" -END . +PROC MAIN + IF 2 9 % 0 == DO + ''' TODO: come up with a better message to print + maybe something to do with the mod result being 0? ''' + "true branch" + ELSE + ''' i feel like we could mention that the number is odd? or something? ''' + "false branch" + END . +END ``` ### Control-flow @@ -68,14 +72,16 @@ END . DSL currently has IF/ELIF/ELSE blocks and WHILE loops: ``` -IF get-some-number 0 == DO - "the number is zero" . -ELIF get-some-number 1 == DO - "the number is one" . -ELIF get-some-number 2 == DO - "the number is two" . -ELSE - "this number has yet to be discovered by science" . +PROC MAIN + IF get-some-number 0 == DO + "the number is zero" . + ELIF get-some-number 1 == DO + "the number is one" . + ELIF get-some-number 2 == DO + "the number is two" . + ELSE + "this number has yet to be discovered by science" . + END END ``` @@ -83,15 +89,23 @@ END Most characters typically thought-of as 'special' have no special syntactic meaning in DSL. Some exceptions include: +* Sequences of characters that would be parsed as data literals * Double-quotes, which start and end string literals * Three single-quotes in a row, which start and end comment blocks * Other special character sequences already reserved as intrinsic / proc names ``` -''' this is okay ''' -PROC $(*^$%*&#$%# "this is a string that was just printed" . END - -''' this isn't ''' +''' these are okay ''' +PROC foo "this proc has a valid name" . END +PROC +foo- "this proc has a valid name" . END +PROC +fo8o- "this proc has a valid name" . END +PROC $(*^$%*&#$%#]} "this proc has a valid name" . END + +''' these aren't ''' +PROC true "this is a parser error" . END +PROC 123 "this is a parser error" . END +PROC "foo" "this is a parser error" . END PROC "foo "this is a parser error" . END +PROC '''foo''' "this is a parser error" . END ``` |