• Timothee Cour via Digitalmars-d (40/40) Jun 14 2017 Proposal: support reading multiple files (with fake file names) from std...
• Kagamin (2/2) Jun 15 2017 Wouldn't it be better done at the lexer level: it needs to reset

Timothee Cour via Digitalmars-d <digitalmars-d puremagic.com> writes:

Proposal: support reading multiple files (with fake file names) from stdin.

This is a natural extension of
https://issues.dlang.org/show_bug.cgi?id=9287 (Issue 9287 - DMD should
read from stdin when an input file is "-")

Example use case:
* simplify writing bug reports and trying out other peoples's bug reports
* simplify writing unittests that depend on multiple files
* IDE integration where more than 1 file are desired

Proposed syntax: use a delimiter to seperate different modules, with a
(fake) file name.

```
cat module_list.txt | dmd -stdin
```

with cat module_list.txt:
```
pragma(module, "bar/foo1.d");
module foo1;
void test1(){}

pragma(module, "bar/foo2.d");
module foo2; // A module name is required
void test2(){}

// etc

```

Now when sending a bug report involving multiple files, the user
doesn't need to manually re-create the file hierarchy, all he needs is
copy paste to the terminal after dmd -stdin, followed by ^D (or just
cat module_list.txt | dmd -stdin)

The other feature here is introduction of fake file names, which
should behave exactly as the real file names except for initially
reading them. This'll greatly simplify writing compiler unittests, or
writing examples for dub / vibe programs that typically rely on a file
hierarchy. This'll also allow documentation unittests involving
multiple files. There are probably other use cases based on reading
entire packages from a url, etc.

Implementation:
similar to https://github.com/dlang/dmd/pull/6880 :
* read from stdin until EOF, then parse into a map string[string]
(module_contents[fakefilename]), then insert a simple interception
logic that searches inside this map before searching in the
filesystem.

Kagamin <spam here.lot> writes:

Wouldn't it be better done at the lexer level: it needs to reset 
line count, see https://issues.dlang.org/show_bug.cgi?id=2660#c13