Allow accessing multiple return items (#330)

Author: vtereshkov

LICENSE

@@ -1,6 +1,6 @@
 BSD 2-Clause License
 
-Copyright (c) 2020-2023, Vasiliy Tereshkov
+Copyright (c) 2020-2024, Vasiliy Tereshkov
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

doc/lang.md

@@ -943,7 +943,9 @@ m["Hello"]
 
 #### Field or method selector
 
-The field or method selector `.`  accesses a field or method. For accessing a field, it can be applied to a structure that has this field or to a pointer to such a structure. For accessing a method, it can be applied to any declared type `T`  or `^T` such that `^T` is compatible with the type that implements this method. If neither field nor method with the specified name is found, an error is triggered.
+The field or method selector `.` accesses a field or method. For accessing a field, it can be applied to a structure that has this field or to a pointer to such a structure. For accessing a method, it can be applied to any declared type `T`  or `^T` such that `^T` is compatible with the type that implements this method. If neither field nor method with the specified name is found, an error is triggered.
+
+As a special case, the field selector can be applied to the result of a function call that returns an expression list. This expression list is treated as if it were a structure with the fields named `item0`, `item1`, etc.    
 
 Syntax:
 
@@ -956,6 +958,7 @@ Examples:
 ```
 v.x
 data.print
+f().item2
 ```
 
 #### Call selector

playground/umka.js

@@ -17,7 +17,7 @@ enum
 void help(void)
 {
     printf("%s\n", umkaGetVersion());
-    printf("(C) Vasiliy Tereshkov, 2020-2023\n");
+    printf("(C) Vasiliy Tereshkov, 2020-2024\n");
     printf("Usage: umka [<parameters>] <file.um> [<script-parameters>]\n");
     printf("Parameters:\n");
     printf("    -stack <stack-size>     - Set stack size\n");

src/umka.c

@@ -609,7 +609,7 @@ Field *typeAddField(Types *types, Type *structType, Type *fieldType, const char
     else
     {
         // Automatic field naming
-        snprintf(fieldNameBuf, DEFAULT_STR_LEN + 1, "__field%d", structType->numItems);
+        snprintf(fieldNameBuf, DEFAULT_STR_LEN + 1, "item%d", structType->numItems);
         name = fieldNameBuf;
     }
 

src/umka_types.c

@@ -333,6 +333,7 @@ World Hello
 23 45.6 "Hello" 'z'
 ['a' 'b'] ['c' 'd'] ['e' 'f']
 12 -3 17
+8.5 "43"
 
 
 >>> Language tour

tests/expected.log

@@ -8,6 +8,10 @@ p := 'z'
 var i, j, k: [2]char = [2]char{'a', 'b'}, [2]char{'c', 'd'}, [2]char{'e', 'f'}
 var l, m, n: real = 12, -3, 17
 
+fn foo(x: int): (real, str) {
+    return x + 1, sprintf("[%v]", x + 1)
+}
+
 fn test*() {
     if a, b, c := f(3, false); a < 3 {
         printf("%v %v %v\n", a, b, c)
@@ -34,6 +38,8 @@ fn test*() {
     printf("%v %v %v %v\n", u, v, w, p)     
     printf("%v %v %v\n", i, j, k)
     printf("%v %v %v\n", l, m, n)
+
+    printf("%v %v\n", foo(7).item0 + 0.5, slice(foo(42).item1, 1, 3))
 }
 
 fn main() {