Documentation
¶
Index ¶
- Constants
- func IsLValue(expr Expr) bool
- func PosErrorf(pos Position, format string, args ...interface{}) error
- func SpecialVarIndex(name string) int
- func SpecialVarName(index int) string
- func Walk(v Visitor, node Node)
- func WalkExprList(v Visitor, exprs []Expr)
- func WalkStmtList(v Visitor, stmts []Stmt)
- type Action
- type ArrayExpr
- type AssignExpr
- type AugAssignExpr
- type BinaryExpr
- type BlockStmt
- type BreakStmt
- type CallExpr
- type CondExpr
- type ContinueStmt
- type DeleteStmt
- type DoWhileStmt
- type ExitStmt
- type Expr
- type ExprStmt
- type FieldExpr
- type ForInStmt
- type ForStmt
- type Function
- type GetlineExpr
- type IfStmt
- type InExpr
- type IncrExpr
- type IndexExpr
- type MultiExpr
- type NamedFieldExpr
- type NextStmt
- type Node
- type NumExpr
- type PositionError
- type PrintStmt
- type PrintfStmt
- type Program
- type RegExpr
- type ResolvedProgram
- type ReturnStmt
- type Stmt
- type Stmts
- type StrExpr
- type UnaryExpr
- type UserCallExpr
- type VarExpr
- type VarScope
- type Visitor
- type WhileStmt
Constants ¶
const ( V_ILLEGAL = iota V_ARGC V_CONVFMT V_FILENAME V_FNR V_FS V_INPUTMODE V_NF V_NR V_OFMT V_OFS V_ORS V_OUTPUTMODE V_RLENGTH V_RS V_RSTART V_RT V_SUBSEP V_LAST = V_SUBSEP )
Variables ¶
This section is empty.
Functions ¶
func IsLValue ¶
IsLValue returns true if the given expression can be used as an lvalue (on the left-hand side of an assignment, in a ++ or -- operation, or as the third argument to sub or gsub).
func SpecialVarIndex ¶
SpecialVarIndex returns the "index" of the special variable, or 0 if it's not a special variable.
func SpecialVarName ¶
SpecialVarName returns the name of the special variable by index.
func Walk ¶
Walk traverses an AST in depth-first order: It starts by calling v.Visit(node); if node is nil, it does nothing. If the visitor w returned by v.Visit(node) is not nil, Walk is invoked recursively with visitor w for each of the non-nil children of node, followed by a call of w.Visit(nil).
func WalkExprList ¶
WalkExprList walks a visitor over a list of expression AST nodes
func WalkStmtList ¶
WalkStmtList walks a visitor over a list of statement AST nodes
Types ¶
type ArrayExpr ¶
ArrayExpr is an array reference. Not really a stand-alone expression, except as an argument to split() or a user function call.
type AssignExpr ¶
AssignExpr is an expression like x = 1234.
func (*AssignExpr) String ¶
func (e *AssignExpr) String() string
type AugAssignExpr ¶
AugAssignExpr is an assignment expression like x += 5.
func (*AugAssignExpr) String ¶
func (e *AugAssignExpr) String() string
type BinaryExpr ¶
BinaryExpr is an expression like 1 + 2.
func (*BinaryExpr) String ¶
func (e *BinaryExpr) String() string
type BlockStmt ¶
type BlockStmt struct {
Body Stmts
Start Position
End Position
}
BlockStmt is a stand-alone block like { print "x" }.
type BreakStmt ¶
type BreakStmt struct {
Start Position
End Position
}
BreakStmt is a break statement.
type CallExpr ¶
type CallExpr struct {
Func Token
Args []Expr
}
CallExpr is a builtin function call like length($1).
type ContinueStmt ¶
type ContinueStmt struct {
Start Position
End Position
}
ContinueStmt is a continue statement.
func (*ContinueStmt) EndPos ¶
func (s *ContinueStmt) EndPos() Position
func (*ContinueStmt) StartPos ¶
func (s *ContinueStmt) StartPos() Position
func (*ContinueStmt) String ¶
func (s *ContinueStmt) String() string
type DeleteStmt ¶
DeleteStmt is a statement like delete a[k].
func (*DeleteStmt) EndPos ¶
func (s *DeleteStmt) EndPos() Position
func (*DeleteStmt) StartPos ¶
func (s *DeleteStmt) StartPos() Position
func (*DeleteStmt) String ¶
func (s *DeleteStmt) String() string
type DoWhileStmt ¶
DoWhileStmt is a do-while loop.
func (*DoWhileStmt) EndPos ¶
func (s *DoWhileStmt) EndPos() Position
func (*DoWhileStmt) StartPos ¶
func (s *DoWhileStmt) StartPos() Position
func (*DoWhileStmt) String ¶
func (s *DoWhileStmt) String() string
type ExitStmt ¶
type ExitStmt struct {
Status Expr
Start Position
End Position
}
ExitStmt is an exit statement.
type ExprStmt ¶
type ExprStmt struct {
Expr Expr
Start Position
End Position
}
ExprStmt is statement like a bare function call: my_func(x).
type ForInStmt ¶
type ForInStmt struct {
Var *VarExpr
Array *ArrayExpr
BodyStart Position
Body Stmts
Start Position
End Position
}
ForInStmt is a for loop like for (k in a) print k, a[k].
type ForStmt ¶
type ForStmt struct {
Pre Stmt
Cond Expr
Post Stmt
BodyStart Position
Body Stmts
Start Position
End Position
}
ForStmt is a C-like for loop: for (i=0; i<10; i++) print i.
type GetlineExpr ¶
GetlineExpr is an expression read from file or pipe input.
func (*GetlineExpr) String ¶
func (e *GetlineExpr) String() string
type IfStmt ¶
type IfStmt struct {
Cond Expr
BodyStart Position
Body Stmts
Else Stmts
Start Position
End Position
}
IfStmt is an if or if-else statement.
type MultiExpr ¶
type MultiExpr struct {
Exprs []Expr
}
MultiExpr isn't an interpretable expression, but it's used as a pseudo-expression for print[f] parsing.
type NamedFieldExpr ¶
type NamedFieldExpr struct {
Field Expr
}
NamedFieldExpr is an expression like @"name".
func (*NamedFieldExpr) String ¶
func (e *NamedFieldExpr) String() string
type Node ¶
type Node interface {
// contains filtered or unexported methods
}
Node is an interface to be satisfied by all AST elements. We need it to be able to work with AST in a generic way, like in ast.Walk().
type PositionError ¶
type PositionError struct {
// Source line/column position where the error occurred.
Position Position
// Error message.
Message string
}
PositionError represents an error bound to specific position in source.
func (*PositionError) Error ¶
func (e *PositionError) Error() string
Error returns a formatted version of the error, including the line and column numbers.
type PrintfStmt ¶
PrintfStmt is a statement like printf "%3d", 1234.
func (*PrintfStmt) EndPos ¶
func (s *PrintfStmt) EndPos() Position
func (*PrintfStmt) StartPos ¶
func (s *PrintfStmt) StartPos() Position
func (*PrintfStmt) String ¶
func (s *PrintfStmt) String() string
type RegExpr ¶
type RegExpr struct {
Regex string
}
RegExpr is a stand-alone regex expression, equivalent to: $0 ~ /regex/.
type ResolvedProgram ¶
ResolvedProgram is a parsed AWK program + additional data prepared by resolve step needed for subsequent interpretation
type ReturnStmt ¶
type ReturnStmt struct {
Value Expr
Start Position
End Position
}
ReturnStmt is a return statement.
func (*ReturnStmt) EndPos ¶
func (s *ReturnStmt) EndPos() Position
func (*ReturnStmt) StartPos ¶
func (s *ReturnStmt) StartPos() Position
func (*ReturnStmt) String ¶
func (s *ReturnStmt) String() string
type Stmt ¶
type Stmt interface {
Node
StartPos() Position // position of first character belonging to the node
EndPos() Position // position of first character immediately after the node
String() string
// contains filtered or unexported methods
}
Stmt is the abstract syntax tree for any AWK statement.
type UnaryExpr ¶
type UnaryExpr struct {
Op Token
Value Expr
}
UnaryExpr is an expression like -1234.
type UserCallExpr ¶
type UserCallExpr struct {
Native bool // false = AWK-defined function, true = native Go func
Index int
Name string
Args []Expr
Pos Position
}
UserCallExpr is a user-defined function call like my_func(1, 2, 3)
Index is the resolved function index used by the interpreter; Name is the original name used by String().
func UserCall ¶
func UserCall(name string, args []Expr, pos Position) *UserCallExpr
UserCall is a constructor for *UserCallExpr
func (*UserCallExpr) String ¶
func (e *UserCallExpr) String() string
type VarExpr ¶
VarExpr is a variable reference (special var, global, or local). Index is the resolved variable index used by the interpreter; Name is the original name used by String().
type Visitor ¶
A Visitor's Visit method is invoked for each node encountered by Walk. If the result visitor w is not nil, Walk visits each of the children of node with the visitor w, followed by a call of w.Visit(nil).
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