there can now be multiple functions with the same name. The most recently declared one will be preferred if multiple would be valid.

docs/statements.md

@@ -0,0 +1,130 @@
+# mers statements overview
+
+This is the documentation for mers statements.
+In code, statements are represented by `SStatement`, `SStatementEnum`, `RStatement`, and `RStatementEnum`.
+
+## Value
+
+A statement that always returns a certain value: `10`, `"Hello, World"`, ...
+
+## Code block
+
+Code blocks are a single statement, but they can contain any number of statements.
+They have their own scope, so local variables declared in them aren't accessible from outside.
+
+They return whatever the last statement they contain returns. Empty code blocks (ones without any statements: `{}`) return `[]`.
+
+    list := [1, 2, 3, 4 ...]
+    sum := {
+      // a temporary variable that only exists in this block
+      counter := 0
+      for elem list {
+        &counter = counter + elem
+      }
+      // the final value will be returned from the block and then assigned to sum.
+      counter
+    }
+
+## Tuple and list
+
+These statements contain any number of statements and return the returned values in order as a tuple or list.
+
+    // x is a tuple and has type [int string float]
+    x := [
+      get_num(),
+      get_text(),
+      12.5
+    ]
+    // y is a list and has type [int/string/float ...]
+    x := [
+      get_num(),
+      get_text(),
+      12.5
+    ...]
+
+## Variable
+
+These statements retrieve the value from a variable name:
+
+    x := "my value"
+    println(
+      x // <- this is a variable statement - it gets the "my value" from above so the println function can use it.
+    )
+
+They can also get references if the variable name is prefixed with the `&` symbol:
+
+    debug(&x) // type is &string
+
+This is why `&` is required to assign to a variable:
+
+    x = "something else" // can't assign to string!
+    &x = "something else" // only data behind references can be changed - we can assign to &string.
+
+## Function call
+
+Function calls give some data to a function and return the result from that function.
+
+There are 3 kinds of function calls:
+
+- calls to builtin functions
+- calls to library functions
+- calls to custom functions
+
+Anonymous functions are called using the builtin `run` function.
+
+## If statement
+
+Allow for conditional execution of code paths:
+
+    if condition() {
+      // do something
+    }
+
+    if condition() {
+      // do something
+    } else {
+      // do something else
+    }
+
+## Loop
+
+Executes code repeatedly:
+
+    counter := 0
+    loop {
+      &counter = counter + 1
+      println("c: " + counter.to_string())
+    }
+
+## For loop
+
+## Switch
+
+## Match
+
+## Enum
+
+Wrap a value in an enum: `EnumName: <statement>`
+
+# dot-chains
+
+Statements can be followed by the dot `.` character. This has different meanings depending on what comes after the dot:
+
+## A function call
+
+In this case, the statement before the dot is prepended to the function arguments:
+
+    a.func(b, c)
+    func(a, b, c)
+
+## An integer
+
+Gets the n-th thing from a tuple (uses zero-based indexing):
+
+    [1, "2", 3.0].1 == "2"
+
+If the value before the dot is a reference to a tuple, a reference to the thing inside the tuple will be obtained:
+
+    x := [1, "2", 3.0]
+    // we assign to the "2", which changes it.
+    &x.1 = "4"

examples/functions_double_definitions.mers

@@ -0,0 +1,27 @@
+type person [string int]
+fn name(p person/&person) p.0
+fn age(p person/&person) p.1
+
+type village [[float float] string]
+fn name(v village/&village) v.1
+fn location(v village/&village) v.0
+fn x_coordinate(v village/&village) v.0.0
+fn y_coordinate(v village/&village) v.0.1
+
+
+
+customer := ["Max M.", 43]
+home_town := [[12.3, 5.09], "Maxburg"]
+
+debug(customer)
+debug(customer.name())
+debug(&customer.name())
+
+debug(home_town)
+debug(home_town.name())
+debug(home_town.location())
+
+println(
+    "Hello, " + customer.name()
+    + " from " + home_town.name()
+)

mers/src/lang/code_runnable.rs

@@ -19,8 +19,8 @@ pub enum RStatementEnum {
     List(Vec<RStatement>),
     Variable(Arc<Mutex<VData>>, VType, bool),
     FunctionCall(Arc<RFunction>, Vec<RStatement>),
-    BuiltinFunction(BuiltinFunction, Vec<RStatement>),
+    BuiltinFunctionCall(BuiltinFunction, Vec<RStatement>),
-    LibFunction(usize, usize, Vec<RStatement>, VType),
+    LibFunctionCall(usize, usize, Vec<RStatement>, VType),
     Block(RBlock),
     If(RStatement, RStatement, Option<RStatement>),
     Loop(RStatement),
@@ -186,8 +186,8 @@ impl RStatementEnum {
                 }
                 func.run(info)
             }
-            Self::BuiltinFunction(v, args) => v.run(args, info),
+            Self::BuiltinFunctionCall(v, args) => v.run(args, info),
-            Self::LibFunction(libid, fnid, args, _) => {
+            Self::LibFunctionCall(libid, fnid, args, _) => {
                 info.libs[*libid].run_fn(*fnid, args.iter().map(|arg| arg.run(info)).collect())
             }
             Self::Block(b) => b.run(info),
@@ -343,7 +343,7 @@ impl RStatementEnum {
             Self::FunctionCall(f, args) => {
                 f.out_vt(&args.iter().map(|v| v.out(info)).collect(), info)
             }
-            Self::LibFunction(.., out) => out.clone(),
+            Self::LibFunctionCall(.., out) => out.clone(),
             Self::Block(b) => b.out(info),
             Self::If(_, a, b) => {
                 if let Some(b) = b {
@@ -354,7 +354,7 @@ impl RStatementEnum {
             }
             Self::Loop(c) => c.out(info).matches().1,
             Self::For(_, _, b) => VSingleType::Tuple(vec![]).to() | b.out(info).matches().1,
-            Self::BuiltinFunction(f, args) => {
+            Self::BuiltinFunctionCall(f, args) => {
                 f.returns(args.iter().map(|rs| rs.out(info)).collect(), info)
             }
             Self::Switch(switch_on, cases, force) => {

mers/src/lang/to_runnable.rs

@@ -33,7 +33,7 @@ pub enum ToRunnableError {
     CannotDeclareVariableWithDereference(String),
     CannotDereferenceTypeNTimes(VType, usize, VType),
     FunctionWrongArgCount(String, usize, usize),
-    FunctionWrongArgs(Vec<VType>, String),
+    FunctionWrongArgs(String, Vec<Arc<RFunction>>, Vec<VType>),
     InvalidType {
         expected: VType,
         found: VType,
@@ -87,7 +87,7 @@ impl FormatGs for ToRunnableError {
                     Ok(())
                 },
                 Self::FunctionWrongArgCount(v, a, b) => write!(f, "Tried to call function \"{v}\", which takes {a} arguments, with {b} arguments instead."),
-                Self::FunctionWrongArgs(args, name) => write!(f, "Wrong args for function \"{name}\":{}", args.iter().map(|v| format!(" {v}")).collect::<String>()),
+                Self::FunctionWrongArgs(fn_name, possible_fns, given_types) => write!(f, "Wrong args for function \"{fn_name}\": {} (possible fns: {})", given_types.iter().map(|v| format!(" {v}")).collect::<String>(), ""),
                 Self::InvalidType {
                     expected,
                     found,
@@ -164,7 +164,7 @@ impl FormatGs for ToRunnableError {
 #[derive(Clone)]
 struct LInfo {
     vars: HashMap<String, (Arc<Mutex<VData>>, VType)>,
-    fns: HashMap<String, Arc<RFunction>>,
+    fns: HashMap<String, Vec<Arc<RFunction>>>,
 }
 
 pub fn to_runnable(
@@ -461,25 +461,37 @@ fn statement_adv(
                 }
             }
             let arg_types: Vec<_> = rargs.iter().map(|v| v.out(ginfo)).collect();
-            if let Some(func) = linfo.fns.get(v) {
+            if let Some(funcs) = linfo.fns.get(v) {
-                if let Some(_out) = check_fn_args(
+                'find_func: {
-                    &arg_types,
+                    for func in funcs.iter().rev() {
-                    &func
+                        if let Some(_out) = check_fn_args(
-                        .input_output_map
+                            &arg_types,
-                        .iter()
+                            &func
-                        .map(|v| (v.0.iter().map(|v| v.clone().to()).collect(), v.1.to_owned()))
+                                .input_output_map
-                        .collect(),
+                                .iter()
-                    ginfo,
+                                .map(|v| {
-                ) {
+                                    (v.0.iter().map(|v| v.clone().to()).collect(), v.1.to_owned())
-                    RStatementEnum::FunctionCall(func.clone(), rargs)
+                                })
-                } else {
+                                .collect(),
-                    return Err(ToRunnableError::FunctionWrongArgs(arg_types, v.to_owned()));
+                            ginfo,
+                        ) {
+                            break 'find_func RStatementEnum::FunctionCall(
+                                Arc::clone(&func),
+                                rargs,
+                            );
+                        }
+                    }
+                    return Err(ToRunnableError::FunctionWrongArgs(
+                        v.to_owned(),
+                        funcs.iter().map(|v| Arc::clone(v)).collect(),
+                        arg_types,
+                    ));
                 }
             } else {
                 if let Some(builtin) = BuiltinFunction::get(v) {
                     let arg_types = rargs.iter().map(|v| v.out(ginfo)).collect();
                     if builtin.can_take(&arg_types, ginfo) {
-                        RStatementEnum::BuiltinFunction(builtin, rargs)
+                        RStatementEnum::BuiltinFunctionCall(builtin, rargs)
                     } else {
                         return Err(ToRunnableError::WrongInputsForBuiltinFunction(
                             builtin,
@@ -493,7 +505,7 @@ fn statement_adv(
                         let lib = &ginfo.libs[*libid];
                         let libfn = &lib.registered_fns[*fnid];
                         if let Some(fn_out) = check_fn_args(&arg_types, &libfn.1, ginfo) {
-                            RStatementEnum::LibFunction(*libid, *fnid, rargs, fn_out.clone())
+                            RStatementEnum::LibFunctionCall(*libid, *fnid, rargs, fn_out.clone())
                         } else {
                             return Err(ToRunnableError::WrongArgsForLibFunction(
                                 v.to_owned(),
@@ -507,18 +519,17 @@ fn statement_adv(
             }
         }
         SStatementEnum::FunctionDefinition(name, f) => {
+            let f = Arc::new(function(f, ginfo, linfo.clone())?);
             if let Some(name) = name {
                 // named function => add to global functions
-                linfo
+                let f = Arc::clone(&f);
-                    .fns
+                if let Some(vec) = linfo.fns.get_mut(name) {
-                    .insert(name.clone(), Arc::new(function(f, ginfo, linfo.clone())?));
+                    vec.push(f);
-                RStatementEnum::Value(VDataEnum::Tuple(vec![]).to())
+                } else {
-            } else {
+                    linfo.fns.insert(name.clone(), vec![f]);
-                // anonymous function => return as value
+                }
-                RStatementEnum::Value(
-                    VDataEnum::Function(Arc::new(function(f, ginfo, linfo.clone())?)).to(),
-                )
             }
+            RStatementEnum::Value(VDataEnum::Function(f).to())
         }
         SStatementEnum::Block(b) => RStatementEnum::Block(block(&b, ginfo, linfo.clone())?),
         SStatementEnum::If(c, t, e) => RStatementEnum::If(