Added variadic functions

TOKEN_DOT_DOT_DOT was added to the lexer
variadic.cosmo was added to the examples directory

examples/variadic.cosmo

@@ -0,0 +1,15 @@
+// adds all args passed (expects numbers)
+function add(start, ...args) 
+    // starting at `start`, add up all numbers passed
+    local total = start
+    for val in args do
+        total = total + val
+    end
+
+    return total
+end
+
+print("add(100) -> " .. add(100))
+print("add(100, 1, 2, 3, 4) -> " .. add(100, 1, 2, 3, 4))
+print("add(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) -> " .. add(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
+print("add(-54, 2, 3, 4, 5, 6, 7, 8, 9, 10) -> " .. add(-54, 2, 3, 4, 5, 6, 7, 8, 9, 10))

src/clex.c

@@ -316,7 +316,7 @@ CToken cosmoL_scanToken(CLexState *state) {
         case '-': 
             return match(state, '-') ? makeToken(state, TOKEN_MINUS_MINUS) : makeToken(state, TOKEN_MINUS);
         case '.': 
-            return match(state, '.') ? makeToken(state, TOKEN_DOT_DOT) : makeToken(state, TOKEN_DOT);
+            return match(state, '.') ? (match(state, '.') ? makeToken(state, TOKEN_DOT_DOT_DOT) : makeToken(state, TOKEN_DOT_DOT)) : makeToken(state, TOKEN_DOT);
         case '!':
             return match(state, '=') ? makeToken(state, TOKEN_BANG_EQUAL) : makeToken(state, TOKEN_BANG);
         case '=':

src/clex.h

@@ -15,6 +15,7 @@ typedef enum {
     TOKEN_COLON,
     TOKEN_DOT,
     TOKEN_DOT_DOT,
+    TOKEN_DOT_DOT_DOT,
     TOKEN_MINUS,
     TOKEN_MINUS_MINUS,
     TOKEN_PLUS,

src/cobj.c

@@ -128,6 +128,7 @@ CObjFunction *cosmoO_newFunction(CState *state) {
     CObjFunction *func = (CObjFunction*)cosmoO_allocateBase(state, sizeof(CObjFunction), COBJ_FUNCTION);
     func->args = 0;
     func->upvals = 0;
+    func->variadic = false;
     func->name = NULL;
     func->module = NULL;
 

src/cobj.h

@@ -64,6 +64,7 @@ typedef struct CObjFunction {
     CChunk chunk;
     int args;
     int upvals;
+    int variadic;
     CObjString *name;
     CObjString *module; // name of the "module"
 } CObjFunction;

src/cparse.c

@@ -713,7 +713,6 @@ static void predecrement(CParseState *pstate, bool canAssign) {
     increment(pstate, -1);
 }
 
-
 ParseRule ruleTable[] = {
     [TOKEN_LEFT_PAREN]      = {group, call_, PREC_CALL},
     [TOKEN_RIGHT_PAREN]     = {NULL, NULL, PREC_NONE},
@@ -725,6 +724,7 @@ ParseRule ruleTable[] = {
     [TOKEN_COLON]           = {NULL, NULL, PREC_NONE},
     [TOKEN_DOT]             = {NULL, dot, PREC_CALL},
     [TOKEN_DOT_DOT]         = {NULL, concat, PREC_CONCAT},
+    [TOKEN_DOT_DOT_DOT]     = {NULL, NULL, PREC_NONE},
     [TOKEN_MINUS]           = {unary, binary, PREC_TERM},
     [TOKEN_MINUS_MINUS]     = {predecrement, NULL, PREC_TERM},
     [TOKEN_PLUS]            = {NULL, binary, PREC_TERM},
@@ -1051,6 +1051,9 @@ static void function(CParseState *pstate, FunctionType type) {
     consume(pstate, TOKEN_LEFT_PAREN, "Expected '(' after identifier.");
     if (!check(pstate, TOKEN_RIGHT_PAREN)) {
         do {
+            if (check(pstate, TOKEN_DOT_DOT_DOT))
+                break;
+            
             // add arg to function
             compiler.function->args++;
             if (compiler.function->args > UINT16_MAX - 1) { // -1 since the function would already be on the stack
@@ -1058,11 +1061,19 @@ static void function(CParseState *pstate, FunctionType type) {
             }
 
             // parse identifier for param (force them to be a local)
-            uint16_t funcIdent = parseVariable(pstate, "Expected identifier for function!", true);
+            uint16_t funcIdent = parseVariable(pstate, "Expected identifier for parameter!", true);
             defineVariable(pstate, funcIdent, true);
             valuePushed(pstate, 1); // they *will* be populated during runtime
         } while (match(pstate, TOKEN_COMMA));
     }
+
+    if (match(pstate, TOKEN_DOT_DOT_DOT)) { // marks a function as variadic, now we expect an identifer for the populated variadic dictionary
+        uint16_t vari = parseVariable(pstate, "Expected identifier for variadic dictionary!", true);
+        defineVariable(pstate, vari, true);
+        valuePushed(pstate, 1);
+        compiler.function->variadic = true;
+    }
+
     consume(pstate, TOKEN_RIGHT_PAREN, "Expected ')' after parameters.");
 
     // compile function block

src/cvm.c

@@ -141,7 +141,7 @@ static inline void callCFunction(CState *state, CosmoCFunction cfunc, int args,
         nres = nresults;
 
     // remember where the return values are
-    CValue* results = cosmoV_getTop(state, nres-1);
+    StkPtr results = cosmoV_getTop(state, nres-1);
 
     state->top = savedBase + offset; // set stack
 
@@ -155,14 +155,32 @@ static inline void callCFunction(CState *state, CosmoCFunction cfunc, int args,
 }
 
 bool call(CState *state, CObjClosure *closure, int args, int nresults, int offset) {
-    // missmatched args, thats an obvious user error, so error.
+    CObjFunction *func = closure->function;
-    if (args != closure->function->args) {
+
-        cosmoV_error(state, "Expected %d parameters for %s, got %d!", closure->function->args, closure->function->name == NULL ? UNNAMEDCHUNK : closure->function->name->str, args);
+    // if the function is variadic and theres more args than parameters, push the args into a dictionary
+    if (func->variadic && args >= func->args) {
+        int extraArgs = args - func->args;
+        StkPtr variStart = cosmoV_getTop(state, extraArgs-1);
+
+        // push key & value pairs
+        for (int i = 0; i < extraArgs; i++) {
+            cosmoV_pushNumber(state, i);
+            cosmoV_pushValue(state, *(variStart + i));
+        }
+
+        cosmoV_makeDictionary(state, extraArgs);
+        *variStart = *cosmoV_getTop(state, 0); // move dict on the stack to the vari local
+        state->top -= extraArgs;
+
+        pushCallFrame(state, closure, func->args + 1);
+    } else if (args < func->args) { // too few args passed, obvious user error
+        cosmoV_error(state, "Expected %d arguments for %s, got %d!", closure->function->args, closure->function->name == NULL ? UNNAMEDCHUNK : closure->function->name->str, args);
         return false;
+    } else {
+        // load function into callframe
+        pushCallFrame(state, closure, func->args);
     }
     
-    // load function into callframe
-    pushCallFrame(state, closure, closure->function->args);
 
     // execute
     int nres = cosmoV_execute(state);
@@ -173,12 +191,12 @@ bool call(CState *state, CObjClosure *closure, int args, int nresults, int offse
         nres = nresults;
 
     // remember where the return values are
-    CValue* results = cosmoV_getTop(state, nres-1);
+    StkPtr results = cosmoV_getTop(state, nres-1);
 
     // pop the callframe and return results :)
     popCallFrame(state, offset);
 
-    // push the return value back onto the stack
+    // push the return values back onto the stack
     memmove(state->top, results, sizeof(CValue) * nres); // copies the return values to the top of the stack
     state->top += nres; // and make sure to move state->top to match