forked from OSchip/llvm-project
81 lines
2.2 KiB
ReStructuredText
81 lines
2.2 KiB
ReStructuredText
=====
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llgoi
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=====
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Introduction
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============
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llgoi is an interactive REPL for Go. It supports expressions, statements,
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most declarations and imports, including binary imports from the standard
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library and source imports from ``$GOPATH``.
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Example usage
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=============
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.. code-block:: none
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(llgo) 1+1
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#0 untyped int = 2
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(llgo) x := 1
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x untyped int = 1
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(llgo) x++
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(llgo) x
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#0 int = 2
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(llgo) import "fmt"
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(llgo) fmt.Println("hello world")
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hello world
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#0 int = 12
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#1 error (<nil>) = <nil>
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(llgo) for i := 0; i != 3; i++ {
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fmt.Println(i)
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}
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0
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1
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2
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(llgo) func foo() {
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fmt.Println("hello decl")
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}
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(llgo) foo()
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hello decl
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(llgo) import "golang.org/x/tools/go/types"
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# golang.org/x/tools/go/ast/astutil
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# golang.org/x/tools/go/exact
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# golang.org/x/tools/go/types
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(llgo) types.Eval("1+1", nil, nil)
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#0 golang.org/x/tools/go/types.TypeAndValue = {mode:4 Type:untyped int Value:2}
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#1 error (<nil>) = <nil>
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Expressions
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===========
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Expressions can be evaluated by entering them at the llgoi prompt. The
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result of evaluating the expression is displayed as if printed with the
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format string ``"%+v"``. If the expression has multiple values (e.g. calls),
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each value is displayed separately.
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Declarations
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============
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Declarations introduce new entities into llgoi's scope. For example, entering
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``x := 1`` introduces into the scope a variable named ``x`` with an initial
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value of 1. In addition to short variable declarations (i.e. variables declared
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with ``:=``), llgoi supports constant declarations, function declarations,
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variable declarations and type declarations.
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Imports
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=======
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To import a package, enter ``import`` followed by the name of a package
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surrounded by quotes. This introduces the package name into llgoi's
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scope. The package may be a standard library package, or a source package on
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``$GOPATH``. In the latter case, llgoi will first compile the package and
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its dependencies.
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Statements
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==========
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Aside from declarations and expressions, the following kinds of statements
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can be evaluated by entering them at the llgoi prompt: IncDec statements,
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assignments, go statements, blocks, if statements, switch statements, select
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statements and for statements.
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