349 lines
8.5 KiB
Go
349 lines
8.5 KiB
Go
package ini
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
)
|
|
|
|
// State enums for the parse table
|
|
const (
|
|
InvalidState = iota
|
|
// stmt -> value stmt'
|
|
StatementState
|
|
// stmt' -> MarkComplete | op stmt
|
|
StatementPrimeState
|
|
// value -> number | string | boolean | quoted_string
|
|
ValueState
|
|
// section -> [ section'
|
|
OpenScopeState
|
|
// section' -> value section_close
|
|
SectionState
|
|
// section_close -> ]
|
|
CloseScopeState
|
|
// SkipState will skip (NL WS)+
|
|
SkipState
|
|
// SkipTokenState will skip any token and push the previous
|
|
// state onto the stack.
|
|
SkipTokenState
|
|
// comment -> # comment' | ; comment'
|
|
// comment' -> MarkComplete | value
|
|
CommentState
|
|
// MarkComplete state will complete statements and move that
|
|
// to the completed AST list
|
|
MarkCompleteState
|
|
// TerminalState signifies that the tokens have been fully parsed
|
|
TerminalState
|
|
)
|
|
|
|
// parseTable is a state machine to dictate the grammar above.
|
|
var parseTable = map[ASTKind]map[TokenType]int{
|
|
ASTKindStart: map[TokenType]int{
|
|
TokenLit: StatementState,
|
|
TokenSep: OpenScopeState,
|
|
TokenWS: SkipTokenState,
|
|
TokenNL: SkipTokenState,
|
|
TokenComment: CommentState,
|
|
TokenNone: TerminalState,
|
|
},
|
|
ASTKindCommentStatement: map[TokenType]int{
|
|
TokenLit: StatementState,
|
|
TokenSep: OpenScopeState,
|
|
TokenWS: SkipTokenState,
|
|
TokenNL: SkipTokenState,
|
|
TokenComment: CommentState,
|
|
TokenNone: MarkCompleteState,
|
|
},
|
|
ASTKindExpr: map[TokenType]int{
|
|
TokenOp: StatementPrimeState,
|
|
TokenLit: ValueState,
|
|
TokenSep: OpenScopeState,
|
|
TokenWS: ValueState,
|
|
TokenNL: SkipState,
|
|
TokenComment: CommentState,
|
|
TokenNone: MarkCompleteState,
|
|
},
|
|
ASTKindEqualExpr: map[TokenType]int{
|
|
TokenLit: ValueState,
|
|
TokenWS: SkipTokenState,
|
|
TokenNL: SkipState,
|
|
},
|
|
ASTKindStatement: map[TokenType]int{
|
|
TokenLit: SectionState,
|
|
TokenSep: CloseScopeState,
|
|
TokenWS: SkipTokenState,
|
|
TokenNL: SkipTokenState,
|
|
TokenComment: CommentState,
|
|
TokenNone: MarkCompleteState,
|
|
},
|
|
ASTKindExprStatement: map[TokenType]int{
|
|
TokenLit: ValueState,
|
|
TokenSep: OpenScopeState,
|
|
TokenOp: ValueState,
|
|
TokenWS: ValueState,
|
|
TokenNL: MarkCompleteState,
|
|
TokenComment: CommentState,
|
|
TokenNone: TerminalState,
|
|
TokenComma: SkipState,
|
|
},
|
|
ASTKindSectionStatement: map[TokenType]int{
|
|
TokenLit: SectionState,
|
|
TokenOp: SectionState,
|
|
TokenSep: CloseScopeState,
|
|
TokenWS: SectionState,
|
|
TokenNL: SkipTokenState,
|
|
},
|
|
ASTKindCompletedSectionStatement: map[TokenType]int{
|
|
TokenWS: SkipTokenState,
|
|
TokenNL: SkipTokenState,
|
|
TokenLit: StatementState,
|
|
TokenSep: OpenScopeState,
|
|
TokenComment: CommentState,
|
|
TokenNone: MarkCompleteState,
|
|
},
|
|
ASTKindSkipStatement: map[TokenType]int{
|
|
TokenLit: StatementState,
|
|
TokenSep: OpenScopeState,
|
|
TokenWS: SkipTokenState,
|
|
TokenNL: SkipTokenState,
|
|
TokenComment: CommentState,
|
|
TokenNone: TerminalState,
|
|
},
|
|
}
|
|
|
|
// ParseAST will parse input from an io.Reader using
|
|
// an LL(1) parser.
|
|
func ParseAST(r io.Reader) ([]AST, error) {
|
|
lexer := iniLexer{}
|
|
tokens, err := lexer.Tokenize(r)
|
|
if err != nil {
|
|
return []AST{}, err
|
|
}
|
|
|
|
return parse(tokens)
|
|
}
|
|
|
|
// ParseASTBytes will parse input from a byte slice using
|
|
// an LL(1) parser.
|
|
func ParseASTBytes(b []byte) ([]AST, error) {
|
|
lexer := iniLexer{}
|
|
tokens, err := lexer.tokenize(b)
|
|
if err != nil {
|
|
return []AST{}, err
|
|
}
|
|
|
|
return parse(tokens)
|
|
}
|
|
|
|
func parse(tokens []Token) ([]AST, error) {
|
|
start := Start
|
|
stack := newParseStack(3, len(tokens))
|
|
|
|
stack.Push(start)
|
|
s := newSkipper()
|
|
|
|
loop:
|
|
for stack.Len() > 0 {
|
|
k := stack.Pop()
|
|
|
|
var tok Token
|
|
if len(tokens) == 0 {
|
|
// this occurs when all the tokens have been processed
|
|
// but reduction of what's left on the stack needs to
|
|
// occur.
|
|
tok = emptyToken
|
|
} else {
|
|
tok = tokens[0]
|
|
}
|
|
|
|
step := parseTable[k.Kind][tok.Type()]
|
|
if s.ShouldSkip(tok) {
|
|
// being in a skip state with no tokens will break out of
|
|
// the parse loop since there is nothing left to process.
|
|
if len(tokens) == 0 {
|
|
break loop
|
|
}
|
|
|
|
step = SkipTokenState
|
|
}
|
|
|
|
switch step {
|
|
case TerminalState:
|
|
// Finished parsing. Push what should be the last
|
|
// statement to the stack. If there is anything left
|
|
// on the stack, an error in parsing has occurred.
|
|
if k.Kind != ASTKindStart {
|
|
stack.MarkComplete(k)
|
|
}
|
|
break loop
|
|
case SkipTokenState:
|
|
// When skipping a token, the previous state was popped off the stack.
|
|
// To maintain the correct state, the previous state will be pushed
|
|
// onto the stack.
|
|
stack.Push(k)
|
|
case StatementState:
|
|
if k.Kind != ASTKindStart {
|
|
stack.MarkComplete(k)
|
|
}
|
|
expr := newExpression(tok)
|
|
stack.Push(expr)
|
|
case StatementPrimeState:
|
|
if tok.Type() != TokenOp {
|
|
stack.MarkComplete(k)
|
|
continue
|
|
}
|
|
|
|
if k.Kind != ASTKindExpr {
|
|
return nil, NewParseError(
|
|
fmt.Sprintf("invalid expression: expected Expr type, but found %T type", k),
|
|
)
|
|
}
|
|
|
|
k = trimSpaces(k)
|
|
expr := newEqualExpr(k, tok)
|
|
stack.Push(expr)
|
|
case ValueState:
|
|
// ValueState requires the previous state to either be an equal expression
|
|
// or an expression statement.
|
|
//
|
|
// This grammar occurs when the RHS is a number, word, or quoted string.
|
|
// equal_expr -> lit op equal_expr'
|
|
// equal_expr' -> number | string | quoted_string
|
|
// quoted_string -> " quoted_string'
|
|
// quoted_string' -> string quoted_string_end
|
|
// quoted_string_end -> "
|
|
//
|
|
// otherwise
|
|
// expr_stmt -> equal_expr (expr_stmt')*
|
|
// expr_stmt' -> ws S | op S | MarkComplete
|
|
// S -> equal_expr' expr_stmt'
|
|
switch k.Kind {
|
|
case ASTKindEqualExpr:
|
|
// assiging a value to some key
|
|
k.AppendChild(newExpression(tok))
|
|
stack.Push(newExprStatement(k))
|
|
case ASTKindExpr:
|
|
k.Root.raw = append(k.Root.raw, tok.Raw()...)
|
|
stack.Push(k)
|
|
case ASTKindExprStatement:
|
|
root := k.GetRoot()
|
|
children := root.GetChildren()
|
|
if len(children) == 0 {
|
|
return nil, NewParseError(
|
|
fmt.Sprintf("invalid expression: AST contains no children %s", k.Kind),
|
|
)
|
|
}
|
|
|
|
rhs := children[len(children)-1]
|
|
|
|
if rhs.Root.ValueType != QuotedStringType {
|
|
rhs.Root.ValueType = StringType
|
|
rhs.Root.raw = append(rhs.Root.raw, tok.Raw()...)
|
|
|
|
}
|
|
|
|
children[len(children)-1] = rhs
|
|
k.SetChildren(children)
|
|
|
|
stack.Push(k)
|
|
}
|
|
case OpenScopeState:
|
|
if !runeCompare(tok.Raw(), openBrace) {
|
|
return nil, NewParseError("expected '['")
|
|
}
|
|
|
|
stmt := newStatement()
|
|
stack.Push(stmt)
|
|
case CloseScopeState:
|
|
if !runeCompare(tok.Raw(), closeBrace) {
|
|
return nil, NewParseError("expected ']'")
|
|
}
|
|
|
|
k = trimSpaces(k)
|
|
stack.Push(newCompletedSectionStatement(k))
|
|
case SectionState:
|
|
var stmt AST
|
|
|
|
switch k.Kind {
|
|
case ASTKindStatement:
|
|
// If there are multiple literals inside of a scope declaration,
|
|
// then the current token's raw value will be appended to the Name.
|
|
//
|
|
// This handles cases like [ profile default ]
|
|
//
|
|
// k will represent a SectionStatement with the children representing
|
|
// the label of the section
|
|
stmt = newSectionStatement(tok)
|
|
case ASTKindSectionStatement:
|
|
k.Root.raw = append(k.Root.raw, tok.Raw()...)
|
|
stmt = k
|
|
default:
|
|
return nil, NewParseError(
|
|
fmt.Sprintf("invalid statement: expected statement: %v", k.Kind),
|
|
)
|
|
}
|
|
|
|
stack.Push(stmt)
|
|
case MarkCompleteState:
|
|
if k.Kind != ASTKindStart {
|
|
stack.MarkComplete(k)
|
|
}
|
|
|
|
if stack.Len() == 0 {
|
|
stack.Push(start)
|
|
}
|
|
case SkipState:
|
|
stack.Push(newSkipStatement(k))
|
|
s.Skip()
|
|
case CommentState:
|
|
if k.Kind == ASTKindStart {
|
|
stack.Push(k)
|
|
} else {
|
|
stack.MarkComplete(k)
|
|
}
|
|
|
|
stmt := newCommentStatement(tok)
|
|
stack.Push(stmt)
|
|
default:
|
|
return nil, NewParseError(fmt.Sprintf("invalid state with ASTKind %v and TokenType %v", k, tok))
|
|
}
|
|
|
|
if len(tokens) > 0 {
|
|
tokens = tokens[1:]
|
|
}
|
|
}
|
|
|
|
// this occurs when a statement has not been completed
|
|
if stack.top > 1 {
|
|
return nil, NewParseError(fmt.Sprintf("incomplete expression: %v", stack.container))
|
|
}
|
|
|
|
// returns a sublist which exludes the start symbol
|
|
return stack.List(), nil
|
|
}
|
|
|
|
// trimSpaces will trim spaces on the left and right hand side of
|
|
// the literal.
|
|
func trimSpaces(k AST) AST {
|
|
// trim left hand side of spaces
|
|
for i := 0; i < len(k.Root.raw); i++ {
|
|
if !isWhitespace(k.Root.raw[i]) {
|
|
break
|
|
}
|
|
|
|
k.Root.raw = k.Root.raw[1:]
|
|
i--
|
|
}
|
|
|
|
// trim right hand side of spaces
|
|
for i := len(k.Root.raw) - 1; i > 0; i-- {
|
|
if !isWhitespace(k.Root.raw[i]) {
|
|
break
|
|
}
|
|
|
|
k.Root.raw = k.Root.raw[:len(k.Root.raw)-1]
|
|
i--
|
|
}
|
|
|
|
return k
|
|
}
|