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- fixed Go statement syntax (only notational change)
- simplified Assignment syntax (only notational change) - added TODOs - made old text invisible by moving it into HTML comment R=r DELTA=107 (4 added, 95 deleted, 8 changed) OCL=15972 CL=15987
This commit is contained in:
Robert Griesemer
parent
d448d18cb4
commit
b9f8b9c43a
111
doc/go_spec.txt
111
doc/go_spec.txt
@ -49,6 +49,8 @@ Open issues according to gri:
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[ ] Do composite literals create a new literal each time (gri thinks yes)
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[ ] consider syntactic notation for composite literals to make them parseable w/o type information
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[ ] nil and interfaces - can we test for nil, what does it mean, etc.
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[ ] type switch or some form of type test needed
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[ ] what is the meaning of typeof()
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Decisions in need of integration into the doc:
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@ -1343,10 +1345,6 @@ Implementation restriction: A function literal can reference only
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its parameters, global variables, and variables declared within the
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function literal.
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TODO: Should a function literal return a value of the function type
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instead of the pointer to the function? Seems more consistent with
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the other uses and composite literals.
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Primary expressions
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----
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@ -1812,9 +1810,7 @@ Note that ++ and -- are not operators for expressions.
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Assignments
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----
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Assignment = SingleAssignment | TupleAssignment .
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SingleAssignment = PrimaryExpr assign_op Expression .
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TupleAssignment = PrimaryExprList assign_op ExpressionList .
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Assignment = PrimaryExprList assign_op ExpressionList .
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PrimaryExprList = PrimaryExpr { "," PrimaryExpr } .
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assign_op = [ add_op | mul_op ] "=" .
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@ -2035,12 +2031,13 @@ Go statements
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----
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A go statement starts the execution of a function as an independent
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concurrent thread of control within the same address space. Unlike
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with a function, the next line of the program does not wait for the
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function to complete.
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concurrent thread of control within the same address space. PrimaryExpr
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must evaluate into a function call.
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GoStat = "go" Call .
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GoStat = "go" PrimaryExpr .
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Unlike with a regular function call, program execution does not wait
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for the invoked function to complete.
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go Server()
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go func(ch chan <- bool) { for { sleep(10); ch <- true; }} (c)
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@ -2597,6 +2594,7 @@ TODO: is there a way to override the default for package main or the
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default for the function name main.main?
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<!--
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----
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----
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UNUSED PARTS OF OLD DOCUMENT go_lang.txt - KEEP AROUND UNTIL NOT NEEDED ANYMORE
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@ -2752,13 +2750,6 @@ There is also a built-in string type, which represents immutable
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strings of bytes.
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Syntax
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----
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The syntax of statements and expressions in Go borrows from the C tradition;
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declarations are loosely derived from the Pascal tradition to allow more
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comprehensible composability of types.
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Interface of a type
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----
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@ -2802,47 +2793,6 @@ TODO: details about reflection
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END]
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Equivalence of types
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---
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TODO: We may need to rethink this because of the new ways interfaces work.
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Types are structurally equivalent: Two types are equivalent (``equal'') if they
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are constructed the same way from equivalent types.
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For instance, all variables declared as "*int" have equivalent type,
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as do all variables declared as "map [string] *chan int".
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More precisely, two struct types are equivalent if they have exactly the same fields
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in the same order, with equal field names and types. For all other composite types,
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the types of the components must be equivalent. Additionally, for equivalent arrays,
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the lengths must be equal (or absent), and for channel types the mode must be equal
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(">", "<", or none). The names of receivers, parameters, or result values of functions
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are ignored for the purpose of type equivalence.
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For instance, the struct type
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struct {
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a int;
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b int;
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f *(m *[32] float, x int, y int) bool
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}
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is equivalent to
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struct {
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a, b int;
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f *F
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}
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where "F" is declared as "func (a *[30 + 2] float, b, c int) (ok bool)".
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Finally, two interface types are equivalent if they both declare the same set of
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methods: For each method in the first interface type there is a method in the
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second interface type with the same method name and equivalent function type,
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and vice versa. Note that the declaration order of the methods is not relevant.
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[OLD
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The nil value
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----
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@ -2867,45 +2817,4 @@ pointer or interface value.
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By default, pointers are initialized to nil.
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TODO: This needs to be revisited.
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[OLD
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TODO: how does this definition jibe with using nil to specify
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conversion failure if the result is not of pointer type, such
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as an any variable holding an int?
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TODO: if interfaces were explicitly pointers, this gets simpler.
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END]
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Expressions
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----
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Expression syntax is based on that of C but with fewer precedence levels.
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Expression = BinaryExpr | UnaryExpr | PrimaryExpr .
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BinaryExpr = Expression binary_op Expression .
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UnaryExpr = unary_op Expression .
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PrimaryExpr =
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identifier | Literal | "(" Expression ")" | "iota" |
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Call | Conversion | Allocation | Index |
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Expression "." identifier | Expression "." "(" Type ")" .
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Call = Expression "(" [ ExpressionList ] ")" .
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Conversion =
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"convert" "(" Type [ "," ExpressionList ] ")" | ConversionType "(" [ ExpressionList ] ")" .
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ConversionType = TypeName | ArrayType | MapType | StructType | InterfaceType .
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Allocation = "new" "(" Type [ "," ExpressionList ] ")" .
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Index = SimpleIndex | Slice .
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SimpleIndex = Expression "[" Expression"]" .
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Slice = Expression "[" Expression ":" Expression "]" .
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TODO
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----
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- TODO: type switch?
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- TODO: words about slices
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- TODO: really lock down semicolons
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- TODO: need to talk (perhaps elsewhere) about libraries, sys.exit(), etc.
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-->
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