mirror of
https://github.com/golang/go
synced 2024-11-24 09:10:24 -07:00
clean up the mess that copyright notices make
R=rsc DELTA=555 (92 added, 38 deleted, 425 changed) OCL=35691 CL=35693
This commit is contained in:
parent
cb1ad7e765
commit
cd7062ef6f
File diff suppressed because it is too large
Load Diff
@ -26,7 +26,7 @@ Hello, World
|
|||||||
|
|
||||||
Let's start in the usual way:
|
Let's start in the usual way:
|
||||||
|
|
||||||
--PROG progs/helloworld.go
|
--PROG progs/helloworld.go /package/ END
|
||||||
|
|
||||||
Every Go source file declares, using a "package" statement, which package it's part of.
|
Every Go source file declares, using a "package" statement, which package it's part of.
|
||||||
The "main" package's "main" function is where the program starts running (after
|
The "main" package's "main" function is where the program starts running (after
|
||||||
@ -52,13 +52,13 @@ Echo
|
|||||||
|
|
||||||
Next up, here's a version of the Unix utility "echo(1)":
|
Next up, here's a version of the Unix utility "echo(1)":
|
||||||
|
|
||||||
--PROG progs/echo.go
|
--PROG progs/echo.go /package/ END
|
||||||
|
|
||||||
This program is small but it's doing a number of new things. In the last example,
|
This program is small but it's doing a number of new things. In the last example,
|
||||||
we saw "func" introducing a function. The keywords "var", "const", and "type"
|
we saw "func" introducing a function. The keywords "var", "const", and "type"
|
||||||
(not used yet) also introduce declarations, as does "import".
|
(not used yet) also introduce declarations, as does "import".
|
||||||
Notice that we can group declarations of the same sort into
|
Notice that we can group declarations of the same sort into
|
||||||
parenthesized, semicolon-separated lists if we want, as on lines 3-6 and 10-13.
|
parenthesized, semicolon-separated lists if we want, as on lines 4-10 and 14-17.
|
||||||
But it's not necessary to do so; we could have said
|
But it's not necessary to do so; we could have said
|
||||||
|
|
||||||
const Space = " "
|
const Space = " "
|
||||||
@ -85,11 +85,11 @@ a naming conflict.
|
|||||||
|
|
||||||
Given "os.Stdout" we can use its "WriteString" method to print the string.
|
Given "os.Stdout" we can use its "WriteString" method to print the string.
|
||||||
|
|
||||||
Having imported the "flag" package, line 8 creates a global variable to hold
|
Having imported the "flag" package, line 12 creates a global variable to hold
|
||||||
the value of echo's "-n" flag. The variable "n_flag" has type "*bool", pointer
|
the value of echo's "-n" flag. The variable "n_flag" has type "*bool", pointer
|
||||||
to "bool".
|
to "bool".
|
||||||
|
|
||||||
In "main.main", we parse the arguments (line 16) and then create a local
|
In "main.main", we parse the arguments (line 20) and then create a local
|
||||||
string variable we will use to build the output.
|
string variable we will use to build the output.
|
||||||
|
|
||||||
The declaration statement has the form
|
The declaration statement has the form
|
||||||
@ -352,7 +352,7 @@ object. We could write
|
|||||||
return n
|
return n
|
||||||
|
|
||||||
but for simple structures like "File" it's easier to return the address of a nonce
|
but for simple structures like "File" it's easier to return the address of a nonce
|
||||||
composite literal, as is done here on line 17.
|
composite literal, as is done here on line 21.
|
||||||
|
|
||||||
We can use the factory to construct some familiar, exported variables of type "*File":
|
We can use the factory to construct some familiar, exported variables of type "*File":
|
||||||
|
|
||||||
@ -370,9 +370,9 @@ multi-value return as a parenthesized list of declarations; syntactically
|
|||||||
they look just like a second parameter list. The function
|
they look just like a second parameter list. The function
|
||||||
"syscall.Open"
|
"syscall.Open"
|
||||||
also has a multi-value return, which we can grab with the multi-variable
|
also has a multi-value return, which we can grab with the multi-variable
|
||||||
declaration on line 27; it declares "r" and "e" to hold the two values,
|
declaration on line 31; it declares "r" and "e" to hold the two values,
|
||||||
both of type "int64" (although you'd have to look at the "syscall" package
|
both of type "int64" (although you'd have to look at the "syscall" package
|
||||||
to see that). Finally, line 28 returns two values: a pointer to the new "File"
|
to see that). Finally, line 35 returns two values: a pointer to the new "File"
|
||||||
and the error. If "syscall.Open" fails, the file descriptor "r" will
|
and the error. If "syscall.Open" fails, the file descriptor "r" will
|
||||||
be negative and "NewFile" will return "nil".
|
be negative and "NewFile" will return "nil".
|
||||||
|
|
||||||
@ -406,7 +406,7 @@ set of such error values.
|
|||||||
|
|
||||||
We can now use our new package:
|
We can now use our new package:
|
||||||
|
|
||||||
--PROG progs/helloworld3.go
|
--PROG progs/helloworld3.go /package/ END
|
||||||
|
|
||||||
The import of ''"./file"'' tells the compiler to use our own package rather than
|
The import of ''"./file"'' tells the compiler to use our own package rather than
|
||||||
something from the directory of installed packages.
|
something from the directory of installed packages.
|
||||||
@ -424,12 +424,12 @@ Rotting cats
|
|||||||
Building on the "file" package, here's a simple version of the Unix utility "cat(1)",
|
Building on the "file" package, here's a simple version of the Unix utility "cat(1)",
|
||||||
"progs/cat.go":
|
"progs/cat.go":
|
||||||
|
|
||||||
--PROG progs/cat.go
|
--PROG progs/cat.go /package/ END
|
||||||
|
|
||||||
By now this should be easy to follow, but the "switch" statement introduces some
|
By now this should be easy to follow, but the "switch" statement introduces some
|
||||||
new features. Like a "for" loop, an "if" or "switch" can include an
|
new features. Like a "for" loop, an "if" or "switch" can include an
|
||||||
initialization statement. The "switch" on line 14 uses one to create variables
|
initialization statement. The "switch" on line 18 uses one to create variables
|
||||||
"nr" and "er" to hold the return values from "f.Read()". (The "if" on line 21
|
"nr" and "er" to hold the return values from "f.Read()". (The "if" on line 25
|
||||||
has the same idea.) The "switch" statement is general: it evaluates the cases
|
has the same idea.) The "switch" statement is general: it evaluates the cases
|
||||||
from top to bottom looking for the first case that matches the value; the
|
from top to bottom looking for the first case that matches the value; the
|
||||||
case expressions don't need to be constants or even integers, as long as
|
case expressions don't need to be constants or even integers, as long as
|
||||||
@ -441,7 +441,7 @@ in a "for" statement, a missing value means "true". In fact, such a "switch"
|
|||||||
is a form of "if-else" chain. While we're here, it should be mentioned that in
|
is a form of "if-else" chain. While we're here, it should be mentioned that in
|
||||||
"switch" statements each "case" has an implicit "break".
|
"switch" statements each "case" has an implicit "break".
|
||||||
|
|
||||||
Line 21 calls "Write()" by slicing the incoming buffer, which is itself a slice.
|
Line 25 calls "Write()" by slicing the incoming buffer, which is itself a slice.
|
||||||
Slices provide the standard Go way to handle I/O buffers.
|
Slices provide the standard Go way to handle I/O buffers.
|
||||||
|
|
||||||
Now let's make a variant of "cat" that optionally does "rot13" on its input.
|
Now let's make a variant of "cat" that optionally does "rot13" on its input.
|
||||||
@ -466,7 +466,7 @@ we have a second implementation of the "reader" interface.
|
|||||||
|
|
||||||
--PROG progs/cat_rot13.go /type.rotate13/ /end.of.rotate13/
|
--PROG progs/cat_rot13.go /type.rotate13/ /end.of.rotate13/
|
||||||
|
|
||||||
(The "rot13" function called on line 38 is trivial and not worth reproducing.)
|
(The "rot13" function called on line 42 is trivial and not worth reproducing.)
|
||||||
|
|
||||||
To use the new feature, we define a flag:
|
To use the new feature, we define a flag:
|
||||||
|
|
||||||
@ -478,7 +478,7 @@ and use it from within a mostly unchanged "cat()" function:
|
|||||||
|
|
||||||
(We could also do the wrapping in "main" and leave "cat()" mostly alone, except
|
(We could also do the wrapping in "main" and leave "cat()" mostly alone, except
|
||||||
for changing the type of the argument; consider that an exercise.)
|
for changing the type of the argument; consider that an exercise.)
|
||||||
Lines 52 through 55 set it all up: If the "rot13" flag is true, wrap the "reader"
|
Lines 56 through 59 set it all up: If the "rot13" flag is true, wrap the "reader"
|
||||||
we received into a "rotate13" and proceed. Note that the interface variables
|
we received into a "rotate13" and proceed. Note that the interface variables
|
||||||
are values, not pointers: the argument is of type "reader", not "*reader",
|
are values, not pointers: the argument is of type "reader", not "*reader",
|
||||||
even though under the covers it holds a pointer to a "struct".
|
even though under the covers it holds a pointer to a "struct".
|
||||||
@ -532,7 +532,7 @@ We can apply "Sort" to any type that implements "Len", "Less", and "Swap".
|
|||||||
The "sort" package includes the necessary methods to allow sorting of
|
The "sort" package includes the necessary methods to allow sorting of
|
||||||
arrays of integers, strings, etc.; here's the code for arrays of "int"
|
arrays of integers, strings, etc.; here's the code for arrays of "int"
|
||||||
|
|
||||||
--PROG progs/sort.go /type.*IntArray/ /swap/
|
--PROG progs/sort.go /type.*IntArray/ /Swap/
|
||||||
|
|
||||||
Here we see methods defined for non-"struct" types. You can define methods
|
Here we see methods defined for non-"struct" types. You can define methods
|
||||||
for any type you define and name in your package.
|
for any type you define and name in your package.
|
||||||
@ -711,7 +711,7 @@ channel, and a prime number. It copies values from the input to the
|
|||||||
output, discarding anything divisible by the prime. The unary communications
|
output, discarding anything divisible by the prime. The unary communications
|
||||||
operator "<-" (receive) retrieves the next value on the channel.
|
operator "<-" (receive) retrieves the next value on the channel.
|
||||||
|
|
||||||
--PROG progs/sieve.go /Copy/ /^}/
|
--PROG progs/sieve.go /Copy.the/ /^}/
|
||||||
|
|
||||||
The generator and filters execute concurrently. Go has
|
The generator and filters execute concurrently. Go has
|
||||||
its own model of process/threads/light-weight processes/coroutines,
|
its own model of process/threads/light-weight processes/coroutines,
|
||||||
@ -736,7 +736,7 @@ together:
|
|||||||
|
|
||||||
--PROG progs/sieve.go /func.main/ /^}/
|
--PROG progs/sieve.go /func.main/ /^}/
|
||||||
|
|
||||||
Line 25 creates the initial channel to pass to "generate", which it
|
Line 29 creates the initial channel to pass to "generate", which it
|
||||||
then starts up. As each prime pops out of the channel, a new "filter"
|
then starts up. As each prime pops out of the channel, a new "filter"
|
||||||
is added to the pipeline and <i>its</i> output becomes the new value
|
is added to the pipeline and <i>its</i> output becomes the new value
|
||||||
of "ch".
|
of "ch".
|
||||||
@ -752,7 +752,7 @@ channel, launches a goroutine internally using a function literal, and
|
|||||||
returns the channel to the caller. It is a factory for concurrent
|
returns the channel to the caller. It is a factory for concurrent
|
||||||
execution, starting the goroutine and returning its connection.
|
execution, starting the goroutine and returning its connection.
|
||||||
|
|
||||||
The function literal notation (lines 8-12) allows us to construct an
|
The function literal notation (lines 12-16) allows us to construct an
|
||||||
anonymous function and invoke it on the spot. Notice that the local
|
anonymous function and invoke it on the spot. Notice that the local
|
||||||
variable "ch" is available to the function literal and lives on even
|
variable "ch" is available to the function literal and lives on even
|
||||||
after "generate" returns.
|
after "generate" returns.
|
||||||
@ -787,7 +787,7 @@ code that invokes the operation and responds to the request:
|
|||||||
|
|
||||||
--PROG progs/server.go /type.binOp/ /^}/
|
--PROG progs/server.go /type.binOp/ /^}/
|
||||||
|
|
||||||
Line 10 defines the name "binOp" to be a function taking two integers and
|
Line 18 defines the name "binOp" to be a function taking two integers and
|
||||||
returning a third.
|
returning a third.
|
||||||
|
|
||||||
The "server" routine loops forever, receiving requests and, to avoid blocking due to
|
The "server" routine loops forever, receiving requests and, to avoid blocking due to
|
||||||
|
@ -10,7 +10,7 @@
|
|||||||
#
|
#
|
||||||
# missing third arg means print one line
|
# missing third arg means print one line
|
||||||
# third arg "END" means proces rest of file
|
# third arg "END" means proces rest of file
|
||||||
# missing second arg means process whole file
|
# missing second arg means process whole file
|
||||||
#
|
#
|
||||||
# examples:
|
# examples:
|
||||||
#
|
#
|
||||||
|
Loading…
Reference in New Issue
Block a user