Add a tag option in the extract program to optionally give an opportunity to tailor some packages in for example the stdlib, for people who is interested in keeping the final binary size as smaller as possible.
Below go generate
```
//go:generate ../cmd/extract/extract -name stdlib -tag stdmime mime mime/multipart mime/quotedprintable
```
produces a header to stdlib/mime-multipart.go
```
// Code generated by 'yaegi extract mime/multipart'. DO NOT EDIT.
// +build go1.16,!go1.17,stdmime
```
When an interpreter type implementing an interface is
used by the runtime, the runtime can extract its type
and create new values using reflect, and call methods
on it. The problem is that there will be no interpreted
method counterpart in this case, which makes wrapper panic.
Allow the String() method wrapper to always succeed and
return an empty string if no interpreted method is present.
This allows scripts to define custom flag.Value types on
which the runtime internally instantiates values using
reflect (see isZeroValue in Go src/flag/flag.go).
This workaround could be generalized to all wrappers if
necessary. At this moment, it is convenient to keep the
default behavior of expecting instantiated interpreter
methods, in order to catch interpreter bugs related to
interfaces.
Fixes#1276.
Store the interpreter value of the interface object to wrap as
a field called IValue, at offset 0 in wrapper structures.
Update extract to include IValue field.
In typeAssert, detect interface wrapper, and dereference the
interpreter value from IValue wrapper field.
Fixes#1166.
The heuristic to generate a package name identifier was incorrect. Now for binary packages, the package identifier is obtained by a symbol, generated by extract, which contains the string argument of package statement in source file. This should ensure an always correct default package identifier.
Fixes#1095.
As per https://golang.org/cmd/go/#hdr-Build_constraints,
using GOOS=android also matches tags and files for GOOS=linux,
so exclude it explicetly to avoid collisions.
Also using GOOS=illumos matches tags and files for GOOS=solaris.
Fixes#843.
This adds type checking to CallExpr (excluding builtin type checking, as that is a PR in its own right) as well as handling any required constant type conversion.
This also changes constant strings and runes to be represented as `constant.Value`. Runes change `rval` type at CFG typing time to avoid having to type at AST time. There are also changes to importSpecs and `stdlib` to account for the string change. With this all `untyped` types should now be `constant.Value`s, although errors are still not returned if this is not the case to be sure we do not break things.
This also fixed a bug in `itype.methods` that would panic if the type was recursive.
