The Go parser is able to detect some (but not all) (re-)decleration errors,
if the DeclarationErrors flag is enabled, which was not done so far.
This PR therefore enables that flag, which allows the removal of some of
the now unneeded code that was recently added to support redeclarations.
Fixes#811
In interactive mode, a line starting with the "func" keyword is usually
"wrapped", by prepending to it a "package main" statement, to make it
a valid piece of Go source code.
However, when the line is actually an anonymous function call, such as:
func() { println(3) }()
then this wrapping is not enough, as this is not valid Go in the global
context. Therefore, this kind of of expression must also be wrapped
inside a main func (as is the default case for most REPL inputs).
Since the detection and handling of such a case turned out to be quite
unelegant, this PR instead introduces a retrying phase when a parsing
error occurs for a particular class of cases. That is to say, when a
"func expression" wrapped in a main package fails to be parsed, it is
then wrapped in a main func before parsing is retried.
N.B. TestEvalScanner has been disabled for this change, because the additional test cases revealed a (most-likely already existing) data race.
Fixes#721
The recent changes that added some redeclaration checks implicitly added more
strictness related to namespaces and scopes which, among other things, broke
some uses that "accidentally" used to work.
For example, given
const script1 = `
import "fmt"
// more code
`
const script2 = `
import "fmt"
// some other code
`
If one Evals script1, then script2, with the same interpreter, without
specifying any scope, as the two fragments would be considered part of the same
(.go file) scope by default, a redeclaration error would be triggered because
import "fmt" is seen twice.
A work-around would have been to specify (a different) i.Name before each Eval
call, so that each script is considered as coming from a different .go file, and
hence are respectively in different scopes with respect to imports.
That lead us to realize we had to make specifying things such as file-scope, and
"incremental mode" (aka REPL), more obvious in the context of an Eval call.
In addition, we want to lay down the foundations for Yaegi being able to behave
more like the go tool wrt to various inputs, i.e. it should be able to take a
package directory, or an import path, as input, instead of just a .go file.
Hence the introduction of a new kind of Eval method (whose signature is not fixed yet):
func (interp *Interpreter) EvalPath(path string) (res reflect.Value, err error)
It partially solves the problem described above because:
1. the path given to EvalPath can be used as the file-scope hint mentioned
above, for now (even though the related implementation details might change).
2. Eval always runs in incremental mode, whereas EvalPath always runs in
non-incremental mode, hence clarifying the situation in that respect.
And to avoid confusion, the Name field of Interpreter is now non-exported,
since it is somewhat redundant with the path argument of EvalPath.
Note that #731 is not fully fixed (and might never be), as a requirement of the
proposed solution is to move the input bits of code into respective files
(instead of leaving them as strings).
Finally, some related bugfixes, documention changes, and some refactoring have
been included. Notably, there is no "empty scope" anymore, i.e. name defaults
to "_.go" when it is not specified.
Updates #731Fixes#778Fixes#798Fixes#789
Co-authored-by: Marc Vertes <mvertes@free.fr>
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.
* fix: detect default comm clause in select from AST
The heuristic to distinguish a default comm clause was too weak.
Make it robust by using AST.
Fixes#646.
* rename test to avoid conflict
* feat: add support for named output variables
Function output parameters are located at the start of the function
frame, uninitialized, as they could be only set through return
statements.
Supporting named output variables requires to:
- identify and allocate symbols corresponding to output names:
done at ident parsing, with the funcRet() helper,
- compute the location of output name in the frame:
done with retRank() helper,
- initialize the frame entry with the zero value of symbol type,
as the symbol can be accessed and written at multiple times,
and return not setting the variable (opposite to unnamed).
Done with frameType() helper, which now takes into account
output parameters.
* refactor: simplify memory management
Perform function frame analysis at pre-order, instead of post-order, to
initialize memory frame, and track value types. Remove all operation
involving unitialized types. Frame memory layout is now build
incrementally, instead of having to perform dedicated tree walks on AST.
Define a new Method action to detect method calls on interface types.
In this case the receiver is resolved from a dynamic type rather than a static one.
Handle method calls where receiver is a pointer.
In typeAssert, always return an interface value with the concrete type, to fix method lookup on interface objects.
Add relevant tests.
Eval returns the value of the root node of AST, so ensure
that node values are propagated back to ExprStmt and BlockStmt,
which should be sufficient to handle evaluation of simple
statements.
The code for comparison operators is now generated by genop.
The support for multiple type has been added.
Missing operators <= and >= are now implemented.
Add `cmd/genop` program to generate operator functions in `interp/op.go`.
For each operator, determine its type, handle argument types conversion if necessary.
Arithmetic operators are added for now. Assign and comparison operators coming in a next commit.
* Fix: multi-assign expression panic
The following corrections are done:
* interp/ast.go: in case of ast.ValueSpec node, fix the decision between
multi-assign or single assign
* interp/cfg.go: in multi-assign parse, skip type symbol if it is
present
* style: fix warnings from golangci-lint printed by `make check`
* style: err assign in if block when possible. Better use of switch/case
* style: err assign in if block when possible
* ast: improve error handling
* ast: handle select
* dyngo: set filename of executed script
* cfg: improve error reporting
* Implement select for receiving channels
* feat(select): add support for sending channels in case clauses
* test: improve tests on select
* feat(select): add support for "default" case
