| Index: doc/go_tutorial.txt |
| =================================================================== |
| --- a/doc/go_tutorial.txt |
| +++ b/doc/go_tutorial.txt |
| @@ -47,6 +47,33 @@ |
| Later we'll have much more to say about printing. |
| +Semicolons |
| +---- |
| + |
| +You might have noticed that our program has no semicolons. In Go |
| +code, the only place you typically see semicolons is separating the |
| +clauses of "for" loops and the like; they are not necessary after |
| +every statement. |
| + |
| +In fact, what happens is that the formal language uses semicolons, |
| +much as in C or Java, but they are inserted automatically |
| +at the end of every line that looks like the end of a statement. You |
| +don't need to type them yourself. |
| + |
| +For details about how this is done you can see the language |
| +specification, but in practice all you need to know is that you |
| +never need to put a semicolon at the end of a line. (You can put |
| +them in if you want to write multiple statements per line.) As an |
| +extra help, you can also leave out a semicolon immediately before |
| +a closing brace. |
| + |
| +This approach makes for clean-looking, semicolon-free code. The |
| +one surprise is that it's important to put the opening |
| +brace of a construct such as an "if" statement on the same line as |
| +the "if"; if you don't, there are situations that may not compile |
| +or may give the wrong result. The language forces the brace style |
| +to some extent. |
| + |
| Compiling |
| ---- |
| @@ -84,27 +111,12 @@ |
| we saw "func" introduce a function. The keywords "var", "const", and "type" |
| (not used yet) also introduce declarations, as does "import". |
| Notice that we can group declarations of the same sort into |
| -parenthesized, semicolon-separated lists if we want, as on lines 7-10 and 14-17. |
| +parenthesized lists, one item per line, as on lines 7-10 and 14-17. |
| But it's not necessary to do so; we could have said |
| const Space = " " |
| const Newline = "\n" |
| -Semicolons aren't needed here; in fact, semicolons are unnecessary after any |
| -top-level declaration, although they are needed as separators <i>within</i> |
| -a parenthesized list of declarations. |
| - |
| -You can use semicolons just the way you would in C, C++, or Java, but if you |
| -prefer you can also leave them out in many cases. They <i>separate</i> statements |
| -rather than terminate them, so they aren't needed (but are still OK) at the end of the last |
| -statement in a block. |
| -They're also optional after braces, as in C. |
| -Have a look at the source to "echo". |
| -The only necessary semicolons in that program are on lines 8, 15, and 21 |
| -and of course between the elements of the "for" loop on line 22. |
| -The ones on line 9, 16, 26, and 31 are optional but are there because a semicolon |
| -on the end of a list of statements makes it easier to edit the list later. |
| - |
| This program imports the ""os"" package to access its "Stdout" variable, of type |
| "*os.File". The "import" statement is actually a declaration: in its general form, |
| as used in our ``hello world'' program, |
| @@ -634,7 +646,7 @@ |
| 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 |
| ---PROG progs/print.go 'NR==14' 'NR==17' |
| +--PROG progs/print.go 'NR==14' 'NR==20' |
| is |
| @@ -647,7 +659,7 @@ |
| and adds a newline. The output of each of these two lines is identical |
| to that of the "Printf" call above. |
| ---PROG progs/print.go 'NR==18' 'NR==19' |
| +--PROG progs/print.go 'NR==21' 'NR==22' |
| 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 |
