diff options
Diffstat (limited to 'examples/how_do_i.nom')
| -rw-r--r-- | examples/how_do_i.nom | 119 |
1 files changed, 88 insertions, 31 deletions
diff --git a/examples/how_do_i.nom b/examples/how_do_i.nom index 18c0a89..f7b5c0b 100644 --- a/examples/how_do_i.nom +++ b/examples/how_do_i.nom @@ -13,29 +13,27 @@ use "core/control_flow.nom" # How do I import all the files in a directory? use "core" -# Set a variable? +# How do I print stuff? +say "Hello world!" + +# How do I set a variable? %x <- 1 %str <- "Hello world" # Expressions that are more than just literal values require parentheses: %x <- (2 + 3) -# Modify a variable? -%foobar <- 100 -# As a shorthand, you can type: -%foobar +<- 1 -# which does the same thing as: -%foobar <- (%foobar + 1) +# How do I modify a variable? +%x <- (%x + 1) +# Or, as a shorthand, you can do this to increment a variable: +%x +<- 1 -# Print stuff? -say "Hello world!" - -# Define a mutli-line string? +# How do I define a mutli-line string? %mutli_str <- ".." Start with "..", then put lines below it that are indented one level. The string will continue until the indentation ends. -# Format a string? +# How do I put values inside a string? %format_str <- ".." Strings can contain a backslash followed by a variable, list, dict, or parenthesized expression. This escaped value will be converted to a readable string, like so: @@ -44,7 +42,7 @@ say "Hello world!" If you need to use a plain ol' backslash, you can do \\ <-- that %format_str2 <- "Single-line strings can contain escape sequences like \", \\, \n, \065, and \x0A" -# Define a list? +# How do I define a list? %my_list <- [1,2,"hello"] #.. Really long lists can use [..] followed by a bunch of indented values delimited by commas and/or newlines @@ -54,7 +52,7 @@ say "Hello world!" 7 8,9,10 -# Use a list? +# How do I use a list? %my_list <- ["first item", "second item", "third item"] # Lists are 1-indexed because they're implemented as Lua tables, so this prints "first item" say %my_list.1 @@ -62,19 +60,19 @@ say %my_list.1 %my_list.1 <- "ONE!!!" say (length of %my_list) -# Define a dictionary/hash map? +# How do I define a dictionary/hash map? %my_dict <- {x: 99, y: 101} %my_dict <- {..} x: 101, y: 2 "99 bottles": 99 653: 292 -# Use a dict? +# How do I use a dict? # Dicts are also implemented as Lua tables, so they're accessed and modified the same way as lists say %my_dict.x %my_dict.x <- 9999 -# Do conditional branching? +# How do I do conditional branching? if: 1 < 10 say "1 is indeed < 10" @@ -96,7 +94,7 @@ when * else say "this is the default case" -# Do a switch statement? +# How do I do a switch statement? when 3 = ? * 0 * 1 @@ -107,7 +105,7 @@ when 3 = ? * else say "this won't print" -# Loop over a list (a foreach loop)? +# How do I loop over a list (a foreach loop)? %list <- [1,2,3] for %x in %list say "For %x loop #\%x" @@ -115,7 +113,7 @@ for %x in %list for all %list say "For all loop #\%" -# Loop over a number range? +# How do I loop over a number range? # This is inclusive, so it will loop over 1,2, and 3 for %i from 1 to 3 say "For %i from 1 to 3 loop #\%i" @@ -127,7 +125,7 @@ for %even from 0 to 5 by 2 for %backwards from 3 to 1 by -1 say "Backwards #\%backwards" -# While loops: +# How do I do a 'while' loop? %x <- 1 repeat while: %x <= 3 say "repeat while loop #\%x" @@ -138,7 +136,7 @@ repeat until: %x > 3 say "repeat until loop #\%x" %x +<- 1 -# Infinite loop: +# How do I do an infinite loop? %x <- 1 repeat say "repeat loop #\%x" @@ -146,7 +144,7 @@ repeat if: %x > 3 stop repeating -# GOTOs: +# How do I do a 'goto'? do %x <- 1 === %again === @@ -157,13 +155,14 @@ do say "finished going to" -# Function definition: +# How do I define a function/method/procedure? +# In nomsu, they're called "action"s, and they can be declared like this: action [say both %first and also %second] say %first # Function arguments are accessed just like variables say %second -# Functions can use "return" to return a value early +# Actions can use "return" to return a value early action [first fibonacci above %n] %f1 <- 0 %f2 <- 1 @@ -176,7 +175,7 @@ action [first fibonacci above %n] say (first fibonacci above 10) -# Functions can have aliases, which may or may not have the arguments in different order +# Actions can have aliases, which may or may not have the arguments in different order action [..] I hate %worse_things more than %better_things I think %worse_things are worse than %better_things @@ -188,18 +187,18 @@ I like "dogs" more than "cats" I think "chihuahuas" are worse than "corgis" -#.. Function calls can have parts of the function's name spread throughout. - Everything that's not a literal value is treated as part of the function's name +#.. Actions can have parts of the action's name spread throughout. + Everything that's not a literal value is treated as part of the action's name say both "Hello" and also "again!" -# Functions can even have their name at the end: +# Actions can even start with a parameter action [%what_she_said is what she said] say %what_she_said say "-- she said" "Howdy pardner" is what she said -#.. The language only reserves []{}().,:;% as special characters, so functions +#.. The language only reserves []{}().,:;% as special characters, so actions can have really funky names! action [>> %foo_bar $$$^ --> % @& _~-^-~_~-^ %1 !] say %foo_bar @@ -214,7 +213,7 @@ action [% と言う] "\(%)世界" say (%こんにちは と言う) -# Math and logic operations are just treated the same as function calls in the syntax +# Math and logic operations are just treated the same as actions in the syntax say (2 + 3) #.. So you can define your own operators, although they will need to be parenthesized to play nicely with other operators @@ -222,6 +221,7 @@ action [%a ++ %b] 2 * (%a + %b) say (1 ++ (2 * 3)) + # How do I do grouping? # Expressions can be grouped by enclosing parentheses: say (2 + 3) @@ -282,3 +282,60 @@ if (1 > (TWENTY)) on opposite day say "Lua compiling macros work!" say "It looks like a keyword, but there's no magic here!" + +# How do I use an action as a value? +#.. Well... it's always *possible* to fall back to Lua behavior for something like this: +action [best of %items according to %key_fn] + <- {%best:nil, %best_key:nil} + for all %items + %key <- (=lua "\%key_fn(\%)") + if: (%best is (nil)) or (%key > %best_key) + <- {%best:%, %best_key:%key} + return %best + +immediately + compile [function %var %body] to + Lua value ".." + (function(\(%var as lua expr)) + return \(%body as lua expr) + end) + +say: best of [2,-3,4,-8] according to (function %: % * %) + +#.. But nomsu was mostly designed so that you don't *need* to. Instead of creating a + one-off function to pass to another function and get called a bunch of times, you + could use a macro to generate a single block of code that inlines the expression you + want to use: +immediately + parse [best of %items according to %key_expr] as + result of + <- {%best:nil, %best_key:nil} + for all %items + %key <- %key_expr + if: (%best is (nil)) or (%key > %best_key) + <- {%best:%, %best_key:%key} + return %best +#.. This results in generated code that is more efficient (no function calls in the + inner loop) +say: best of [2,-3,4,-8] according to (% * %) + +#.. In a functional programming language, you might do something like: + doubled = map(list, function(x) return 2 * x end) + to get a new list with every entry multiplied by 2, but it's *much* more readable to + do something like: +%nums <- [1,2,3,4,5] +%double_nums <- ((2 * %num) for %num in %nums) + +#.. Nomsu comes with built-in list comprehensions, but the flexible macro system makes it + incredibly easy to make similar constructs. +immediately + parse [%expr for %key in %list BACKWARDS!] as + result of + %result <- [] + %N <- (length of %list) + for %i = %key in %list + %result.(%N - %i + 1) <- %expr + return %result + +%double_nums <- ((2 * %num) for %num in %nums BACKWARDS!) +say %double_nums |