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docs: fold the prog.sh scripting from makehtml into htmlgen itself.

Browse Source 
This allows us to drop some crufty scripting and provides a firmer
footing for building better tools for preparing documents with source
code inside.

Also eliminate line numbers from the examples and text.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/4650069
This commit is contained in:
Rob Pike 2011-07-04 16:15:14 +10:00
parent a342006207
commit 9cf37c3723
5 changed files with 727 additions and 681 deletions
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108
doc/go_tutorial.txt
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@ -28,7 +28,7 @@ Hello, World
Let's start in the usual way: Let's start in the usual way:
--PROG progs/helloworld.go /package/ END !src progs/helloworld.go /package/ $
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.
It may also import other packages to use their facilities. It may also import other packages to use their facilities.
@ -107,13 +107,13 @@ 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 /package/ END !src progs/echo.go /package/ $
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" introduce a function. The keywords "var", "const", and "type" we saw "func" introduce 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 lists, one item per line, as on lines 7-10 and 14-17. parenthesized lists, one item per line, as in the "import" and "const" clauses here.
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 = " "
@ -163,7 +163,7 @@ or we could go even shorter and write the idiom
The ":=" operator is used a lot in Go to represent an initializing declaration. The ":=" operator is used a lot in Go to represent an initializing declaration.
There's one in the "for" clause on the next line: There's one in the "for" clause on the next line:
--PROG progs/echo.go /for/ !src progs/echo.go /for/
The "flag" package has parsed the arguments and left the non-flag arguments The "flag" package has parsed the arguments and left the non-flag arguments
in a list that can be iterated over in the obvious way. in a list that can be iterated over in the obvious way.
@ -210,7 +210,7 @@ Once you've built a string <i>value</i>, you can't change it, although
of course you can change a string <i>variable</i> simply by of course you can change a string <i>variable</i> simply by
reassigning it. This snippet from "strings.go" is legal code: reassigning it. This snippet from "strings.go" is legal code:
--PROG progs/strings.go /hello/ /ciao/ !src progs/strings.go /hello/ /ciao/
However the following statements are illegal because they would modify However the following statements are illegal because they would modify
a "string" value: a "string" value:
@ -269,7 +269,7 @@ will slice the whole array.
Using slices one can write this function (from "sum.go"): Using slices one can write this function (from "sum.go"):
--PROG progs/sum.go /sum/ /^}/ !src progs/sum.go /sum/ /^}/
Note how the return type ("int") is defined for "sum" by stating it Note how the return type ("int") is defined for "sum" by stating it
after the parameter list. after the parameter list.
@ -386,7 +386,7 @@ An I/O Package
Next we'll look at a simple package for doing file I/O with an Next we'll look at a simple package for doing file I/O with an
open/close/read/write interface. Here's the start of "file.go": open/close/read/write interface. Here's the start of "file.go":
--PROG progs/file.go /package/ /^}/ !src progs/file.go /package/ /^}/
The first few lines declare the name of the The first few lines declare the name of the
package&mdash;"file"&mdash;and then import two packages. The "os" package&mdash;"file"&mdash;and then import two packages. The "os"
@ -416,7 +416,7 @@ will soon give it some exported, upper-case methods.
First, though, here is a factory to create a "File": First, though, here is a factory to create a "File":
--PROG progs/file.go /newFile/ /^}/ !src progs/file.go /newFile/ /^}/
This returns a pointer to a new "File" structure with the file descriptor and name This returns a pointer to a new "File" structure with the file descriptor and name
filled in. This code uses Go's notion of a ''composite literal'', analogous to filled in. This code uses Go's notion of a ''composite literal'', analogous to
@ -433,12 +433,12 @@ 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":
--PROG progs/file.go /var/ /^.$/ !src progs/file.go /var/ /^.$/
The "newFile" function was not exported because it's internal. The proper, The "newFile" function was not exported because it's internal. The proper,
exported factory to use is "OpenFile" (we'll explain that name in a moment): exported factory to use is "OpenFile" (we'll explain that name in a moment):
--PROG progs/file.go /func.OpenFile/ /^}/ !src progs/file.go /func.OpenFile/ /^}/
There are a number of new things in these few lines. First, "OpenFile" returns There are a number of new things in these few lines. First, "OpenFile" returns
multiple values, a "File" and an error (more about errors in a moment). multiple values, a "File" and an error (more about errors in a moment).
@ -468,9 +468,9 @@ the implementation of our "Open" and "Create"; they're trivial
wrappers that eliminate common errors by capturing wrappers that eliminate common errors by capturing
the tricky standard arguments to open and, especially, to create a file: the tricky standard arguments to open and, especially, to create a file:
--PROG progs/file.go /^const/ /^}/ !src progs/file.go /^const/ /^}/
--PROG progs/file.go /func.Create/ /^}/ !src progs/file.go /func.Create/ /^}/
Back to our main story. Back to our main story.
Now that we can build "Files", we can write methods for them. To declare Now that we can build "Files", we can write methods for them. To declare
@ -479,7 +479,7 @@ of that type, placed
in parentheses before the function name. Here are some methods for "*File", in parentheses before the function name. Here are some methods for "*File",
each of which declares a receiver variable "file". each of which declares a receiver variable "file".
--PROG progs/file.go /Close/ END !src progs/file.go /Close/ $
There is no implicit "this" and the receiver variable must be used to access There is no implicit "this" and the receiver variable must be used to access
members of the structure. Methods are not declared within members of the structure. Methods are not declared within
@ -496,7 +496,7 @@ set of such error values.
We can now use our new package: We can now use our new package:
--PROG progs/helloworld3.go /package/ END !src progs/helloworld3.go /package/ $
The ''"./"'' in the import of ''"./file"'' tells the compiler The ''"./"'' in the import of ''"./file"'' tells the compiler
to use our own package rather than to use our own package rather than
@ -520,12 +520,12 @@ 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 /package/ END !src progs/cat.go /package/ $
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 18 uses one to create variables initialization statement. The "switch" statement in "cat" uses one to create variables
"nr" and "er" to hold the return values from the call to "f.Read". (The "if" on line 25 "nr" and "er" to hold the return values from the call to "f.Read". (The "if" a few lines later
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
@ -537,7 +537,7 @@ 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 25 calls "Write" by slicing the incoming buffer, which is itself a slice. The argument to "file.Stdout.Write" is created by slicing the array "buf".
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.
@ -548,7 +548,7 @@ The "cat" subroutine uses only two methods of "f": "Read" and "String",
so let's start by defining an interface that has exactly those two methods. so let's start by defining an interface that has exactly those two methods.
Here is code from "progs/cat_rot13.go": Here is code from "progs/cat_rot13.go":
--PROG progs/cat_rot13.go /type.reader/ /^}/ !src progs/cat_rot13.go /type.reader/ /^}/
Any type that has the two methods of "reader"&mdash;regardless of whatever Any type that has the two methods of "reader"&mdash;regardless of whatever
other methods the type may also have&mdash;is said to <i>implement</i> the other methods the type may also have&mdash;is said to <i>implement</i> the
@ -560,34 +560,32 @@ existing "reader" and does "rot13" on the data. To do this, we just define
the type and implement the methods and with no other bookkeeping, the type and implement the methods and with no other bookkeeping,
we have a second implementation of the "reader" interface. we have a second implementation of the "reader" interface.
--PROG progs/cat_rot13.go /type.rotate13/ /end.of.rotate13/ !src progs/cat_rot13.go /type.rotate13/ /end.of.rotate13/
(The "rot13" function called on line 42 is trivial and not worth reproducing here.) (The "rot13" function called in "Read" is trivial and not worth reproducing here.)
To use the new feature, we define a flag: To use the new feature, we define a flag:
--PROG progs/cat_rot13.go /rot13Flag/ !src progs/cat_rot13.go /rot13Flag/
and use it from within a mostly unchanged "cat" function: and use it from within a mostly unchanged "cat" function:
--PROG progs/cat_rot13.go /func.cat/ /^}/ !src progs/cat_rot13.go /func.cat/ /^}/
(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 56 through 58 set it all up: If the "rot13" flag is true, wrap the "reader" The "if" at the top of "cat" sets 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".
Here it is in action: Here it is in action:
<pre>
$ echo abcdefghijklmnopqrstuvwxyz | ./cat $ echo abcdefghijklmnopqrstuvwxyz | ./cat
abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz
$ echo abcdefghijklmnopqrstuvwxyz | ./cat --rot13 $ echo abcdefghijklmnopqrstuvwxyz | ./cat --rot13
nopqrstuvwxyzabcdefghijklm nopqrstuvwxyzabcdefghijklm
$ $
</pre>
Fans of dependency injection may take cheer from how easily interfaces Fans of dependency injection may take cheer from how easily interfaces
allow us to substitute the implementation of a file descriptor. allow us to substitute the implementation of a file descriptor.
@ -601,9 +599,7 @@ as we saw with "rot13". The type "file.File" implements "reader"; it could also
implement a "writer", or any other interface built from its methods that implement a "writer", or any other interface built from its methods that
fits the current situation. Consider the <i>empty interface</i> fits the current situation. Consider the <i>empty interface</i>
<pre>
type Empty interface {} type Empty interface {}
</pre>
<i>Every</i> type implements the empty interface, which makes it <i>Every</i> type implements the empty interface, which makes it
useful for things like containers. useful for things like containers.
@ -618,17 +614,17 @@ same interface variable.
As an example, consider this simple sort algorithm taken from "progs/sort.go": As an example, consider this simple sort algorithm taken from "progs/sort.go":
--PROG progs/sort.go /func.Sort/ /^}/ !src progs/sort.go /func.Sort/ /^}/
The code needs only three methods, which we wrap into sort's "Interface": The code needs only three methods, which we wrap into sort's "Interface":
--PROG progs/sort.go /interface/ /^}/ !src progs/sort.go /interface/ /^}/
We can apply "Sort" to any type that implements "Len", "Less", and "Swap". 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.*IntSlice/ /Swap/ !src progs/sort.go /type.*IntSlice/ /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.
@ -637,12 +633,12 @@ And now a routine to test it out, from "progs/sortmain.go". This
uses a function in the "sort" package, omitted here for brevity, uses a function in the "sort" package, omitted here for brevity,
to test that the result is sorted. to test that the result is sorted.
--PROG progs/sortmain.go /func.ints/ /^}/ !src progs/sortmain.go /func.ints/ /^}/
If we have a new type we want to be able to sort, all we need to do is If we have a new type we want to be able to sort, all we need to do is
to implement the three methods for that type, like this: to implement the three methods for that type, like this:
--PROG progs/sortmain.go /type.day/ /Swap/ !src progs/sortmain.go /type.day/ /Swap/
Printing Printing
@ -675,7 +671,7 @@ argument. It's easier in many cases in Go. Instead of "%llud" you
can just say "%d"; "Printf" knows the size and signedness of the can just say "%d"; "Printf" knows the size and signedness of the
integer and can do the right thing for you. The snippet integer and can do the right thing for you. The snippet
--PROG progs/print.go 'NR==10' 'NR==11' !src progs/print.go 10 11
prints prints
@ -684,7 +680,7 @@ prints
In fact, if you're lazy the format "%v" will print, in a simple In fact, if you're lazy the format "%v" will print, in a simple
appropriate style, any value, even an array or structure. The output of appropriate style, any value, even an array or structure. The output of
--PROG progs/print.go 'NR==14' 'NR==20' !src progs/print.go 14 20
is is
@ -697,7 +693,7 @@ of "%v" while "Println" inserts spaces between arguments
and adds a newline. The output of each of these two lines is identical and adds a newline. The output of each of these two lines is identical
to that of the "Printf" call above. to that of the "Printf" call above.
--PROG progs/print.go 'NR==21' 'NR==22' !src progs/print.go 21 22
If you have your own type you'd like "Printf" or "Print" to format, If you have your own type you'd like "Printf" or "Print" to format,
just give it a "String" method that returns a string. The print just give it a "String" method that returns a string. The print
@ -705,7 +701,7 @@ routines will examine the value to inquire whether it implements
the method and if so, use it rather than some other formatting. the method and if so, use it rather than some other formatting.
Here's a simple example. Here's a simple example.
--PROG progs/print_string.go 'NR==9' END !src progs/print_string.go 9 $
Since "*testType" has a "String" method, the Since "*testType" has a "String" method, the
default formatter for that type will use it and produce the output default formatter for that type will use it and produce the output
@ -803,7 +799,7 @@ coordinates the communication; as with maps and slices, use
Here is the first function in "progs/sieve.go": Here is the first function in "progs/sieve.go":
--PROG progs/sieve.go /Send/ /^}/ !src progs/sieve.go /Send/ /^}/
The "generate" function sends the sequence 2, 3, 4, 5, ... to its The "generate" function sends the sequence 2, 3, 4, 5, ... to its
argument channel, "ch", using the binary communications operator "&lt;-". argument channel, "ch", using the binary communications operator "&lt;-".
@ -815,7 +811,7 @@ 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 "&lt;-" (receive) retrieves the next value on the channel. operator "&lt;-" (receive) retrieves the next value on the channel.
--PROG progs/sieve.go /Copy.the/ /^}/ !src 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,
@ -838,9 +834,9 @@ on which it can report back:
Back to our prime sieve. Here's how the sieve pipeline is stitched Back to our prime sieve. Here's how the sieve pipeline is stitched
together: together:
--PROG progs/sieve.go /func.main/ /^}/ !src progs/sieve.go /func.main/ /^}/
Line 29 creates the initial channel to pass to "generate", which it The first line of "main" 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".
@ -849,30 +845,30 @@ The sieve program can be tweaked to use a pattern common
in this style of programming. Here is a variant version in this style of programming. Here is a variant version
of "generate", from "progs/sieve1.go": of "generate", from "progs/sieve1.go":
--PROG progs/sieve1.go /func.generate/ /^}/ !src progs/sieve1.go /func.generate/ /^}/
This version does all the setup internally. It creates the output This version does all the setup internally. It creates the output
channel, launches a goroutine running a function literal, and channel, launches a goroutine running 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 12-16) allows us to construct an The function literal notation used in the "go" statement 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.
The same change can be made to "filter": The same change can be made to "filter":
--PROG progs/sieve1.go /func.filter/ /^}/ !src progs/sieve1.go /func.filter/ /^}/
The "sieve" function's main loop becomes simpler and clearer as a The "sieve" function's main loop becomes simpler and clearer as a
result, and while we're at it let's turn it into a factory too: result, and while we're at it let's turn it into a factory too:
--PROG progs/sieve1.go /func.sieve/ /^}/ !src progs/sieve1.go /func.sieve/ /^}/
Now "main"'s interface to the prime sieve is a channel of primes: Now "main"'s interface to the prime sieve is a channel of primes:
--PROG progs/sieve1.go /func.main/ /^}/ !src progs/sieve1.go /func.main/ /^}/
Multiplexing Multiplexing
---- ----
@ -884,41 +880,41 @@ A realistic client-server program is a lot of code, so here is a very simple sub
to illustrate the idea. It starts by defining a "request" type, which embeds a channel to illustrate the idea. It starts by defining a "request" type, which embeds a channel
that will be used for the reply. that will be used for the reply.
--PROG progs/server.go /type.request/ /^}/ !src progs/server.go /type.request/ /^}/
The server will be trivial: it will do simple binary operations on integers. Here's the The server will be trivial: it will do simple binary operations on integers. Here's the
code that invokes the operation and responds to the request: code that invokes the operation and responds to the request:
--PROG progs/server.go /type.binOp/ /^}/ !src progs/server.go /type.binOp/ /^}/
Line 14 defines the name "binOp" to be a function taking two integers and The type declaration makes "binOp" represent 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
a long-running operation, starting a goroutine to do the actual work. a long-running operation, starting a goroutine to do the actual work.
--PROG progs/server.go /func.server/ /^}/ !src progs/server.go /func.server/ /^}/
We construct a server in a familiar way, starting it and returning a channel We construct a server in a familiar way, starting it and returning a channel
connected to it: connected to it:
--PROG progs/server.go /func.startServer/ /^}/ !src progs/server.go /func.startServer/ /^}/
Here's a simple test. It starts a server with an addition operator and sends out Here's a simple test. It starts a server with an addition operator and sends out
"N" requests without waiting for the replies. Only after all the requests are sent "N" requests without waiting for the replies. Only after all the requests are sent
does it check the results. does it check the results.
--PROG progs/server.go /func.main/ /^}/ !src progs/server.go /func.main/ /^}/
One annoyance with this program is that it doesn't shut down the server cleanly; when "main" returns One annoyance with this program is that it doesn't shut down the server cleanly; when "main" returns
there are a number of lingering goroutines blocked on communication. To solve this, there are a number of lingering goroutines blocked on communication. To solve this,
we can provide a second, "quit" channel to the server: we can provide a second, "quit" channel to the server:
--PROG progs/server1.go /func.startServer/ /^}/ !src progs/server1.go /func.startServer/ /^}/
It passes the quit channel to the "server" function, which uses it like this: It passes the quit channel to the "server" function, which uses it like this:
--PROG progs/server1.go /func.server/ /^}/ !src progs/server1.go /func.server/ /^}/
Inside "server", the "select" statement chooses which of the multiple communications Inside "server", the "select" statement chooses which of the multiple communications
listed by its cases can proceed. If all are blocked, it waits until one can proceed; if listed by its cases can proceed. If all are blocked, it waits until one can proceed; if
@ -930,9 +926,9 @@ returns, terminating its execution.
All that's left is to strobe the "quit" channel All that's left is to strobe the "quit" channel
at the end of main: at the end of main:
--PROG progs/server1.go /adder,.quit/ !src progs/server1.go /adder,.quit/
... ...
--PROG progs/server1.go /quit....true/ !src progs/server1.go /quit....true/
There's a lot more to Go programming and concurrent programming in general but this There's a lot more to Go programming and concurrent programming in general but this
quick tour should give you some of the basics. quick tour should give you some of the basics.

157
doc/htmlgen.go
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@ -2,46 +2,80 @@
// Use of this source code is governed by a BSD-style // Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file. // license that can be found in the LICENSE file.
// Process plain text into HTML. // If --html is set, process plain text into HTML.
// - h2's are made from lines followed by a line "----\n" // - h2's are made from lines followed by a line "----\n"
// - tab-indented blocks become <pre> blocks // - tab-indented blocks become <pre> blocks with the first tab deleted
// - blank lines become <p> marks (except inside <pre> tags) // - blank lines become <p> marks (except inside <pre> tags)
// - "quoted strings" become <code>quoted strings</code> // - "quoted strings" become <code>quoted strings</code>
// Lines beginning !src define pieces of program source to be
// extracted from other files and injected as <pre> blocks.
// The syntax is simple: 1, 2, or 3 space-separated arguments:
//
// Whole file:
// !src foo.go
// One line (here the signature of main):
// !src foo.go /^func.main/
// Block of text, determined by start and end (here the body of main):
// !src foo.go /^func.main/ /^}/
//
// Patterns can be /regular.expression/, a decimal number, or $
// to signify the end of the file.
// TODO: the regular expression cannot contain spaces; does this matter?
package main package main
import ( import (
"bufio" "bufio"
"bytes" "bytes"
"flag"
"fmt"
"io/ioutil"
"log" "log"
"os" "os"
"regexp"
"strconv"
"strings"
"template"
) )
var ( var (
lines = make([][]byte, 0, 2000) // probably big enough; grows if not html = flag.Bool("html", true, "process text into HTML")
)
var (
// lines holds the input and is reworked in place during processing.
lines = make([][]byte, 0, 20000)
empty = []byte("") empty = []byte("")
newline = []byte("\n") newline = []byte("\n")
tab = []byte("\t") tab = []byte("\t")
quote = []byte(`"`) quote = []byte(`"`)
indent = []byte{' ', ' ', ' ', ' '} indent = []byte(" ")
sectionMarker = []byte("----\n") sectionMarker = []byte("----\n")
preStart = []byte("<pre>") preStart = []byte("<pre>")
preEnd = []byte("</pre>\n") preEnd = []byte("</pre>\n")
pp = []byte("<p>\n") pp = []byte("<p>\n")
srcPrefix = []byte("!src")
) )
func main() { func main() {
flag.Parse()
read() read()
programs()
if *html {
headings() headings()
coalesce(preStart, foldPre) coalesce(preStart, foldPre)
coalesce(tab, foldTabs) coalesce(tab, foldTabs)
paragraphs() paragraphs()
quotes() quotes()
}
write() write()
} }
// read turns standard input into a slice of lines.
func read() { func read() {
b := bufio.NewReader(os.Stdin) b := bufio.NewReader(os.Stdin)
for { for {
@ -56,6 +90,7 @@ func read() {
} }
} }
// write puts the result on standard output.
func write() { func write() {
b := bufio.NewWriter(os.Stdout) b := bufio.NewWriter(os.Stdout)
for _, line := range lines { for _, line := range lines {
@ -64,8 +99,104 @@ func write() {
b.Flush() b.Flush()
} }
// each time prefix is found on a line, call fold and replace // programs injects source code from !src invocations.
// line with return value from fold. func programs() {
nlines := make([][]byte, 0, len(lines)*3/2)
for _, line := range lines {
if bytes.HasPrefix(line, srcPrefix) {
line = trim(line)[len(srcPrefix):]
prog := srcCommand(string(line))
if *html {
nlines = append(nlines, []byte(fmt.Sprintf("<pre><!--%s\n-->", line)))
}
for _, l := range prog {
nlines = append(nlines, htmlEscape(l))
}
if *html {
nlines = append(nlines, preEnd)
}
} else {
nlines = append(nlines, line)
}
}
lines = nlines
}
// srcCommand processes one !src invocation.
func srcCommand(command string) [][]byte {
// TODO: quoted args so we can have 'a b'?
args := strings.Fields(command)
if len(args) == 0 || len(args) > 3 {
log.Fatal("bad syntax for src command: %s", command)
}
file := args[0]
lines := bytes.SplitAfter(readFile(file), newline)
// File plus zero args: whole file:
// !src file.go
if len(args) == 1 {
return lines
}
start := match(file, 0, lines, string(args[1]))
// File plus one arg: one line:
// !src file.go /foo/
if len(args) == 2 {
return [][]byte{lines[start]}
}
// File plus two args: range:
// !src file.go /foo/ /^}/
end := match(file, start, lines, string(args[2]))
return lines[start : end+1] // +1 to include matched line.
}
// htmlEscape makes sure input is HTML clean, if necessary.
func htmlEscape(input []byte) []byte {
if !*html || bytes.IndexAny(input, `&"<>`) < 0 {
return input
}
var b bytes.Buffer
template.HTMLEscape(&b, input)
return b.Bytes()
}
// readFile reads and returns a file as part of !src processing.
func readFile(name string) []byte {
file, err := ioutil.ReadFile(name)
if err != nil {
log.Fatal(err)
}
return file
}
// match identifies the input line that matches the pattern in a !src invocation.
// If start>0, match lines starting there rather than at the beginning.
func match(file string, start int, lines [][]byte, pattern string) int {
// $ matches the end of the file.
if pattern == "$" {
return len(lines) - 1
}
// Number matches the line.
if i, err := strconv.Atoi(pattern); err == nil {
return i - 1 // Lines are 1-indexed.
}
// /regexp/ matches the line that matches the regexp.
if len(pattern) > 2 && pattern[0] == '/' && pattern[len(pattern)-1] == '/' {
re, err := regexp.Compile(pattern[1 : len(pattern)-1])
if err != nil {
log.Fatal(err)
}
for i := start; i < len(lines); i++ {
if re.Match(lines[i]) {
return i
}
}
log.Fatalf("%s: no match for %s", file, pattern)
}
log.Fatalf("unrecognized pattern: %s", pattern)
return 0
}
// coalesce combines lines. Each time prefix is found on a line,
// it calls fold and replaces the line with return value from fold.
func coalesce(prefix []byte, fold func(i int) (n int, line []byte)) { func coalesce(prefix []byte, fold func(i int) (n int, line []byte)) {
j := 0 // output line number goes up by one each loop j := 0 // output line number goes up by one each loop
for i := 0; i < len(lines); { for i := 0; i < len(lines); {
@ -82,7 +213,7 @@ func coalesce(prefix []byte, fold func(i int) (n int, line []byte)) {
lines = lines[0:j] lines = lines[0:j]
} }
// return the <pre> block as a single slice // foldPre returns the <pre> block as a single slice.
func foldPre(i int) (n int, line []byte) { func foldPre(i int) (n int, line []byte) {
buf := new(bytes.Buffer) buf := new(bytes.Buffer)
for i < len(lines) { for i < len(lines) {
@ -96,7 +227,7 @@ func foldPre(i int) (n int, line []byte) {
return n, buf.Bytes() return n, buf.Bytes()
} }
// return the tab-indented block as a single <pre>-bounded slice // foldTabs returns the tab-indented block as a single <pre>-bounded slice.
func foldTabs(i int) (n int, line []byte) { func foldTabs(i int) (n int, line []byte) {
buf := new(bytes.Buffer) buf := new(bytes.Buffer)
buf.WriteString("<pre>\n") buf.WriteString("<pre>\n")
@ -104,7 +235,7 @@ func foldTabs(i int) (n int, line []byte) {
if !bytes.HasPrefix(lines[i], tab) { if !bytes.HasPrefix(lines[i], tab) {
break break
} }
buf.Write(lines[i]) buf.Write(lines[i][1:]) // delete leading tab.
n++ n++
i++ i++
} }
@ -112,6 +243,7 @@ func foldTabs(i int) (n int, line []byte) {
return n, buf.Bytes() return n, buf.Bytes()
} }
// headings turns sections into HTML sections.
func headings() { func headings() {
b := bufio.NewWriter(os.Stdout) b := bufio.NewWriter(os.Stdout)
for i, l := range lines { for i, l := range lines {
@ -123,6 +255,7 @@ func headings() {
b.Flush() b.Flush()
} }
// paragraphs turns blank lines into paragraph marks.
func paragraphs() { func paragraphs() {
for i, l := range lines { for i, l := range lines {
if bytes.Equal(l, newline) { if bytes.Equal(l, newline) {
@ -131,12 +264,14 @@ func paragraphs() {
} }
} }
// quotes turns "x" in the file into <code>x</code>.
func quotes() { func quotes() {
for i, l := range lines { for i, l := range lines {
lines[i] = codeQuotes(l) lines[i] = codeQuotes(l)
} }
} }
// quotes turns "x" in the line into <code>x</code>.
func codeQuotes(l []byte) []byte { func codeQuotes(l []byte) []byte {
if bytes.HasPrefix(l, preStart) { if bytes.HasPrefix(l, preStart) {
return l return l
@ -162,7 +297,7 @@ func codeQuotes(l []byte) []byte {
return buf.Bytes() return buf.Bytes()
} }
// drop trailing newline // trim drops the trailing newline, if present.
func trim(l []byte) []byte { func trim(l []byte) []byte {
n := len(l) n := len(l)
if n > 0 && l[n-1] == '\n' { if n > 0 && l[n-1] == '\n' {
@ -171,7 +306,7 @@ func trim(l []byte) []byte {
return l return l
} }
// expand tabs to spaces. don't worry about columns. // expandTabs expands tabs to spaces. It doesn't worry about columns.
func expandTabs(l []byte) []byte { func expandTabs(l []byte) []byte {
return bytes.Replace(l, tab, indent, -1) return bytes.Replace(l, tab, indent, -1)
} }

16
doc/makehtml
View File

@ -7,7 +7,6 @@ set -e
TXT=${1:-go_tutorial.txt} # input file TXT=${1:-go_tutorial.txt} # input file
HTML=$(basename $TXT .txt).html # output file (basename) HTML=$(basename $TXT .txt).html # output file (basename)
TMP=TEMP.txt # input to htmlgen
if ! test -w $HTML if ! test -w $HTML
then then
@ -15,17 +14,4 @@ then
exit 1 exit 1
fi fi
if grep -q '^--PROG' $TXT make htmlgen && ./htmlgen < $TXT > $HTML
then
echo >&2 makehtml: processing PROG sections
<$TXT >$TMP awk '
/^--PROG/ { system("sh ./prog.sh "$2" "$3" "$4" "); getline }
/^/ {print}
'
else
cp $TXT $TMP
fi
make htmlgen && ./htmlgen < $TMP > $HTML
rm -f $TMP

72
doc/prog.sh
View File

@ -1,72 +0,0 @@
#!/bin/sh
# Copyright 2009 The Go Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.
# generate HTML for a program excerpt.
# first arg is file name
# second arg is awk pattern to match start line
# third arg is awk pattern to stop processing
#
# missing third arg means print one line
# third arg "END" means proces rest of file
# missing second arg means process whole file
#
# examples:
#
# prog.sh foo.go # whole file
# prog.sh foo.go "/^func.main/" # signature of main
# prog.sh foo.go "/^func.main/" "/^}/ # body of main
#
# non-blank lines are annotated with line number in file
# line numbers are printed %.2d to make them equal-width for nice formatting.
# the format gives a leading 0. the format %2d gives a leading space but
# that appears to confuse sanjay's makehtml formatter into bungling quotes
# because it makes some lines look indented.
echo "<pre> <!-- $* -->"
case $# in
3)
if test "$3" = "END" # $2 to end of file
then
awk '
function LINE() { printf("%.2d\t%s\n", NR, $0) }
BEGIN { printing = 0 }
'$2' { printing = 1; LINE(); getline }
printing { if($0 ~ /./) { LINE() } else { print "" } }
'
else # $2 through $3
awk '
function LINE() { printf("%.2d\t%s\n", NR, $0) }
BEGIN { printing = 0 }
'$2' { printing = 1; LINE(); getline }
'$3' && printing { if(printing) {printing = 0; LINE(); exit} }
printing { if($0 ~ /./) { LINE() } else { print "" } }
'
fi
;;
2) # one line
awk '
function LINE() { printf("%.2d\t%s\n", NR, $0) }
'$2' { LINE(); getline; exit }
'
;;
1) # whole file
awk '
function LINE() { printf("%.2d\t%s\n", NR, $0) }
{ if($0 ~ /./) { LINE() } else { print "" } }
'
;;
*)
echo >&2 usage: prog.sh file.go /func.main/ /^}/
esac <$1 |
sed '
s/&/\&amp;/g
s/"/\&quot;/g
s/</\&lt;/g
s/>/\&gt;/g
'
echo '</pre>'