made syntax cheat sheet a bit clearer

docs/syntax_cheat_sheet.md

@@ -62,6 +62,9 @@
     * this is why `&<var_name> = <statement>` is the way it is.
   + `***<statement_left> = <statement_right>`
     * same as before, but performs dereferences: `&&&&int` becomes `&int` (minus 3 references because 3 `*`s), so a value of type `int` can be assigned to it.
+- destructuring
+  + values can be destructured into tuples or lists (as of right now):
+  + `[a, b] := [10, "some text"]` is effectively the same as `a := 10, b := "some text"`
 
 ## Statements
 
@@ -89,26 +92,26 @@
   + if the statement returns a value that matches, the loop will end and return the matched value
   + the loop's return type is the match of the return type of the statement
 - for loop
-  + `for <var_name> <iterator> <statement>`
+  + `for <assign_to> <iterator> <statement>`
   + in each iteration, the variable will be initialized with a value from the iterator.
   + iterators can be lists, tuples, or functions.
   + for function iterators, as long as the returned value matches, the matched value will be used. if the value doesn't match, the loop ends.
   + if the statement returns a value that matches, the loop will end and return the matched value
   + the loop's return type is the match of the return type of the statement or `[]` (if the loop ends because the iterator ended)
 - switch
-  + `switch <var_name> { <arm1> <arm2> <...> }`
+  + `switch <value> { <arm1> <arm2> <...> }`
-    * where `<armn>` is `<typen> <statementn>`
+    * where `<armn>` is `<typen> <assign_to> <statementn>`
-    * if the variable's value is of type `<typen>`, `<statementn>` will be executed.
+    * if the variable's value is of type `<typen>`, `<statementn>` will be executed with `<value>` assigned to `<assign_to>`.
     * if the variables type is included multiple times, only the first match will be executed.
     * within the statement of an arm, the variables type is that specified in `<typen>`, and not its original type (which may be too broad to work with)
   + `switch! <var_name> { <arm1> <arm2> <...> }`
     * same as above, but all types the variable could have must be covered
     * the additional `[]` in the return type isn't added here since it is impossible not to run the statement of one of the arms.
 - match
-  + `match <var_name> { <arm1> <arm2> <...> }`
+  + `match { <arm1> <arm2> <...> }`
-    * where `<armn>` is `<statement> <statement>`
+    * where `<armn>` is `<(condition) statement> <assign_to> <(action) statement>`
-    * each arm has a condition statement an an action statement.
+    * each arm has a condition statement, something that the matched value will be assigned to, and an action statement.
-    * if the value returned by the condition statement matches, the matched value is assigned to the variable and the action statement is executed.
+    * if the value returned by the condition statement matches, the matched value is assigned to `<assign_to>` and the action statement is executed.
     * only the first matching arm will be executed. if no arm was executed, `[]` is returned.
 - fixed-indexing
   + `<statement>.n` where `n` is a fixed number (not a variable, just `0`, `1`, `2`, ...)

index.html

@@ -9,7 +9,7 @@
 <section class="container">
 <section class="container_left2 code-border">
 <pre><code class="mers-code-snippet">
-fn get_number_input(question string) {<br>    println(question)<br>    input := read_line()<br>    // try to parse to an int, then a float.<br>    in := match input {<br>        input.parse_int() input<br>        input.parse_float() input<br>    }<br>    // 'in' has type int/float/[] because of the match statement<br>    switch! in {<br>        int/float in<br>        // replace [] with an appropriate error before returning<br>        [] Err: "input was not a number."<br>    }<br>    // return type is int/float/Err(string)<br>}<br><br>answer := get_number_input("What is your favorite number?")<br><br>answer.debug() // type: int/float/Err(string)<br>// switch can be used to branch based on a variables type.<br>// switch! indicates that every possible type must be handled.<br>switch! answer {<br>    int {<br>        println("Entered an integer")<br>        answer.debug() // type: int<br>    }<br>    float {<br>        println("Entered a decimal number")<br>        answer.debug() // type: float<br>    }<br>    Err(string) println("Input was not a number!")<br>}<br><br>// wait one second<br>sleep(1)<br><br><br>// function that returns an anonymous function (function object).<br>// anonymous functions can be used as iterators in for-loops.<br>fn square_numbers() {<br>    i := 0<br>    () {<br>        &amp;i = i + 1<br>        i * i<br>    }<br>}<br><br>for num square_numbers() {<br>    println(num.to_string())<br>    // once num is greater than 60, the loop stops.<br>    num.gt(50)<br>}<br></code></pre>
+fn get_number_input(question string) {<br>    println(question)<br>    input := read_line()<br>    // try to parse to an int, then a float.<br>    in := match {<br>        input.parse_int() n n<br>        input.parse_float() n n<br>    }<br>    // 'in' has type int/float/[] because of the match statement<br>    switch! in {<br>        int/float in in<br>        // replace [] with an appropriate error before returning<br>        [] [] Err: "input was not a number."<br>    }<br>    // return type is int/float/Err(string)<br>}<br><br>answer := get_number_input("What is your favorite number?")<br><br>answer.debug() // type: int/float/Err(string)<br>// switch can be used to branch based on a variables type.<br>// switch! indicates that every possible type must be handled.<br>switch! answer {<br>    int num {<br>        println("Entered an integer")<br>        num.debug() // type: int<br>    }<br>    float num {<br>        println("Entered a decimal number")<br>        num.debug() // type: float<br>    }<br>    Err(string) [] println("Input was not a number!")<br>}<br><br>// wait one second<br>sleep(1)<br><br><br>// function that returns an anonymous function (function object).<br>// anonymous functions can be used as iterators in for-loops.<br>fn square_numbers() {<br>    i := 0<br>    () {<br>        &amp;i = i + 1<br>        i * i<br>    }<br>}<br><br>for num square_numbers() {<br>    println(num.to_string())<br>    // once num is greater than 60, the loop stops.<br>    num.gt(50)<br>}<br></code></pre>
 </section>
 <section class="container_right">
 <image

mers/src/lang/code_runnable.rs

@@ -338,9 +338,9 @@ impl RStatementEnum {
                 let switch_on = switch_on.out(info).types;
                 let mut might_return_empty = switch_on.is_empty();
                 let mut out = if *force {
-                    VSingleType::Tuple(vec![]).to()
-                } else {
                     VType::empty()
+                } else {
+                    VSingleType::Tuple(vec![]).to()
                 };
                 for switch_on in switch_on {
                     for (_on_type, _assign_to, case) in cases.iter() {

site/welcome.mers

@@ -2,15 +2,15 @@ fn get_number_input(question string) {
     println(question)
     input := read_line()
     // try to parse to an int, then a float.
-    in := match input {
+    in := match {
-        input.parse_int() input
+        input.parse_int() n n
-        input.parse_float() input
+        input.parse_float() n n
     }
     // 'in' has type int/float/[] because of the match statement
     switch! in {
-        int/float in
+        int/float in in
         // replace [] with an appropriate error before returning
-        [] Err: "input was not a number."
+        [] [] Err: "input was not a number."
     }
     // return type is int/float/Err(string)
 }
@@ -21,15 +21,15 @@ answer.debug() // type: int/float/Err(string)
 // switch can be used to branch based on a variables type.
 // switch! indicates that every possible type must be handled.
 switch! answer {
-    int {
+    int num {
         println("Entered an integer")
-        answer.debug() // type: int
+        num.debug() // type: int
     }
-    float {
+    float num {
         println("Entered a decimal number")
-        answer.debug() // type: float
+        num.debug() // type: float
     }
-    Err(string) println("Input was not a number!")
+    Err(string) [] println("Input was not a number!")
 }
 
 // wait one second