These are syntactical changes to better reflect the communication
operator's new status in the language.
- sending to a channel is now done via a send statement
- there is no binary communication operation anymore which
leads to a reduction of the number of precedence levels
from 6 to 5 (yeah!)
- small semantic change: since a send operation is not part
of the expression syntax anymore, a <- send operator is
binding weaker than any other operator now
- receiving from a channel is done as before via the unary
receive expression
- communication clauses in select statement now can contain
send statements or receive expressions
R=rsc, r, iant, ken2, gri1
CC=golang-dev
https://golang.org/cl/3973051
Close of closed channel panics.
Receive from closed channel never panics,
even if done repeatedly.
Fixes#1349.
Fixes#1419.
R=gri, iant, ken2, r, gri1, r2, iant2, rog, albert.strasheim, niemeyer, ejsherry
CC=golang-dev
https://golang.org/cl/3989042
The default float type is not very useful but for the most basic applications.
For instance, as it is now, using the math package requires conversions for float
variables (the arguments for math functions are usually float64). Typical real
applications tend to specify the floating point precision required.
This proposal removes the predeclared types float and complex. Variable declarations
without type specification but with constant floating point or complex initializer
expressions will assume the type float64 or complex128 respectively.
The predeclared function cmplx is renamed to complex.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/3423041
- use math.Sqrt instead of Math.sqrt
- use float64 for Point fields to match math.Sqrt
- distinguish between Point and Point3D for clarity
- add alignment sizes for complex types
R=r, rsc, iant, ken2
CC=golang-dev
https://golang.org/cl/3420041
Added a "return" to the end of an example which previously threw a compile error if used.
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/3052041
Consistency argument: A valid Go program should
remain valid after stripping leading and trailing
whitespace. This was not true so far if the last
text in the source was a line comment.
R=iant, ken2, r, rsc, r2
CC=golang-dev
https://golang.org/cl/2906041
For elements which are themselves composite literals, the type may
be omitted if it is identical to the element type of the containing
composite literal.
R=r, rsc, iant, ken2
CC=golang-dev
https://golang.org/cl/2661041
Background: The current spec is imprecise with respect to the parsing ambiguity
for composite literals: It says that the ambiguity arises when the TypeName form
of the LiteralType is used. The following code:
if (B) {} ...
is not using the TypeName form (but the parenthesized TypeName form) and thus
could be interpreted as:
if ((B){}) ...
instead of
if B {} ...
Both compilers and gofmt choose the latter interpretation. One could fix the
spec by making the clause regarding the parsing ambiguity more precise ("...using
the _possibly parenthesized_ TypeName form of the LiteralType..."). The alternative
(chosen here) is to simply disallow parenthesized literal types. Except for a single
test case (test/parentype.go) there appears to be no Go code under $GOROOT containing
parenthesized literal types. Furthermore, parentheses are never needed around a
literal type for correct parsing.
R=golang-dev
CC=golang-dev
https://golang.org/cl/1913041
We didn't mention this explicitly during our discussions,
but I think it fits the "identical types are spelled identically"
rule that we used.
R=gri, iant, ken2, r, rsc1
CC=golang-dev
https://golang.org/cl/1698043
Specifically:
- introduced notion of "underlying type"
- removed notion of type compatibility
- consolidated rules about assignment compatibility in
assignment compatibility section
- be consistent with specyfing that nil is the value
for uninitialized variables that can be nil (this
was not specified clearly for pointers, functions, interfaces)
- added/fixed various related links throughout
- clarify language on conversions
R=rsc, r, iant, ken2
CC=golang-dev
https://golang.org/cl/1536041
Specifically:
- Simplified definition of comparison compatibility and folded into
section on comparison operators since it's only used there.
This is a small language change/cleanup. As a consequence:
- An interface value may now be compared against a non-interface value.
- Channels with opposite directions cannot be compared directly anymore
(per discussion with rsc).
R=rsc, r, iant, ken2
CC=golang-dev
https://golang.org/cl/1462041
and adjust conversion rules.
Also:
- clarification of type identity (no language change)
- adjust special rules for channel assignment/comparison to
require identical element types (in correspondence to non-
recursiveness of type compatibility)
R=rsc, iant, ken2, r
CC=golang-dev
https://golang.org/cl/1376042
- also added links to the respective sections
- reformatted section for better (source html) readability
- added missing closing </li>'s in many places
R=r
CC=golang-dev
https://golang.org/cl/1220041
Also: Actual map key must be assignment-compatible with
formal map key type.
Fixes#357.
R=r, iant, rsc, ken2
CC=golang-dev
https://golang.org/cl/673042
This was discussed with Ken and Russ. 6g has been changed,
and both compilers now work this way. This avoids a double
type conversion--first to the float type, then to the complex
type.
R=r
CC=golang-dev, ken2, rsc
https://golang.org/cl/419042
no longer ambiguous at top level, thanks to new semicolon rules.
use gofmt layout for function types.
Fixes#528.
R=gri
CC=golang-dev
https://golang.org/cl/194077
