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Limit top-level statements to a single compilation unit within a program (#3292)

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Reflect LDM decision made on 2020-03-09 to limit top-level statements to a single compilation unit within a program.
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AlekseyTs 2020-03-25 16:28:26 -07:00 committed by GitHub
parent 64da1dcf00
commit 75ddc88a40
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1 changed files with 9 additions and 21 deletions
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30
proposals/Simple-programs.md
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@ -47,18 +47,16 @@ compilation_unit
;
```
In all but one *compilation_unit* the *statement*s must all be local function declarations.
Only one *compilation_unit* is allowed to have *statement*s.
Example:
``` c#
// File 1 - any statements
if (args.Length == 0
|| !int.TryParse(args[0], out int n)
if (System.Environment.CommandLine.Length == 0
|| !int.TryParse(System.Environment.CommandLine, out int n)
|| n < 0) return;
Console.WriteLine(Fib(n).curr);
// File 2 - only local functions
(int curr, int prev) Fib(int i)
{
if (i == 0) return (1, 0);
@ -78,9 +76,7 @@ static class Program
{
static async Task Main()
{
// File 1 statements
// File 2 local functions
// ...
// statements
}
}
```
@ -91,12 +87,7 @@ source code.
The method is designated as the entry point of the program. Explicitly declared methods that by convention
could be considered as an entry point candidates are ignored. A warning is reported when that happens. It is
an error to specify `-main:<type>` compiler switch.
If any one compilation unit has statements other than local function declarations, statements from that
compilation unit occur first. This causes it to be legal for local functions in one file to reference
local variables in another. The order of statement contributions (which would all be local functions)
from other compilation units is undefined.
an error to specify `-main:<type>` compiler switch when there are top-level statements.
Async operations are allowed in top-level statements to the degree they are allowed in statements within
a regular async entry point method. However, they are not required, if `await` expressions and other async
@ -113,13 +104,11 @@ static class $Program
{
static void $Main()
{
// Statements from File 1
if (args.Length == 0
|| !int.TryParse(args[0], out int n)
if (System.Environment.CommandLine.Length == 0
|| !int.TryParse(System.Environment.CommandLine, out int n)
|| n < 0) return;
Console.WriteLine(Fib(n).curr);
// Local functions from File 2
(int curr, int prev) Fib(int i)
{
if (i == 0) return (1, 0);
@ -132,7 +121,6 @@ static class $Program
At the same time an example like this:
``` c#
// File 1
await System.Threading.Tasks.Task.Delay(1000);
System.Console.WriteLine("Hi!");
```
@ -143,7 +131,6 @@ static class $Program
{
static async Task $Main()
{
// Statements from File 1
await System.Threading.Tasks.Task.Delay(1000);
System.Console.WriteLine("Hi!");
}
@ -153,7 +140,8 @@ static class $Program
### Scope of top-level local variables and local functions
Even though top-level local variables and functions are "wrapped"
into the generated entry point method, they should still be in scope throughout the program.
into the generated entry point method, they should still be in scope throughout the program in
every compilation unit.
For the purpose of simple-name evaluation, once the global namespace is reached:
- First, an attempt is made to evaluate the name within the generated entry point method and
only if this attempt fails