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package subex
import (
"fmt"
"main/walk"
)
// A node in the AST of a subex
type SubexAST interface {
compileWith(next SubexState) SubexState
}
// Process the first subex, then the second, splitting the input text in two
type SubexASTConcat struct {
first, second SubexAST
}
func (ast SubexASTConcat) compileWith(next SubexState) SubexState {
return ast.first.compileWith(ast.second.compileWith(next))
}
func (ast SubexASTConcat) String() string {
return fmt.Sprintf("(%v)(%v)", ast.first, ast.second)
}
// Processing a subex and storing the output in a slot instead of outputting it
type SubexASTStore struct {
match SubexAST
slot rune
}
func (ast SubexASTStore) compileWith(next SubexState) SubexState {
return &SubexStoreState {
match: ast.match.compileWith(&SubexNoneState{}),
slot: ast.slot,
next: next,
}
}
func (ast SubexASTStore) String() string {
return fmt.Sprintf("$%c(%v)", ast.slot, ast.match)
}
// Try to run the first subex, if it fails then backtrack and use the second
type SubexASTOr struct {
first, second SubexAST
}
func (ast SubexASTOr) compileWith(next SubexState) SubexState {
return &SubexGroupState {
ast.first.compileWith(next),
ast.second.compileWith(next),
}
}
// Run the content subex as many times as possible as the input is read in
type SubexASTMaximise struct {
content SubexAST
}
func (ast SubexASTMaximise) compileWith(next SubexState) SubexState {
state := &SubexGroupState {
nil,
next,
}
state.first = ast.content.compileWith(state)
return state
}
func (ast SubexASTMaximise) String() string {
return fmt.Sprintf("(%v)*", ast.content)
}
// Run the content subex as few times as possible as the input is read in
type SubexASTMinimise struct {
content SubexAST
}
func (ast SubexASTMinimise) compileWith(next SubexState) SubexState {
state := &SubexGroupState {
next,
nil,
}
state.second = ast.content.compileWith(state)
return state
}
func (ast SubexASTMinimise) String() string {
return fmt.Sprintf("(%v)-", ast.content)
}
// Run the subex as many times as possible but at least min times and at most max times
type SubexASTRepeat struct {
content SubexAST
min, max int
}
func (ast SubexASTRepeat) compileWith(next SubexState) SubexState {
for i := ast.min; i < ast.max; i += 1 {
next = &SubexGroupState {
ast.content.compileWith(next),
next,
}
}
for i := 0; i < ast.min; i += 1 {
next = ast.content.compileWith(next)
}
return next
}
// Read in a single specific Atom and output it unchanged
type SubexASTCopyAtom struct {
atom walk.Atom
}
func (ast SubexASTCopyAtom) compileWith(next SubexState) SubexState {
return &SubexCopyAtomState{
atom: ast.atom,
next: next,
}
}
// Read in any single Atom and output it unchanged
type SubexASTCopyAny struct {}
func (ast SubexASTCopyAny) compileWith(next SubexState) SubexState {
return &SubexCopyAnyState{next}
}
func (ast SubexASTCopyAny) String() string {
return "."
}
// Output a series of Atoms without reading anything from input
type SubexASTOutput struct {
replacement []OutputContent
}
func (ast SubexASTOutput) compileWith(next SubexState) SubexState {
return &SubexOutputState{
content: ast.replacement,
next: next,
}
}
// Try to use a subex but just skip over this if it doesn't match
type SubexASTTry struct {
content SubexAST
}
func (ast SubexASTTry) compileWith(next SubexState) SubexState {
return &SubexGroupState {
ast.content.compileWith(next),
next,
}
}
// Try to skip over this subex but use it should that not match
type SubexASTMaybe struct {
content SubexAST
}
func (ast SubexASTMaybe) compileWith(next SubexState) SubexState {
return &SubexGroupState {
next,
ast.content.compileWith(next),
}
}
// Read in a repeated subex separated by a delimiter. Greedy
type SubexASTJoin struct {
content, delimiter SubexAST
}
func (ast SubexASTJoin) compileWith(next SubexState) SubexState {
afterContentState := &SubexGroupState {
nil,
next,
}
manyContentsState := ast.content.compileWith(afterContentState)
afterContentState.first = ast.delimiter.compileWith(manyContentsState)
return &SubexGroupState {
manyContentsState,
next,
}
}
// Run each input Atom through a map to produce an output Atom
// Atoms not in the map cause this to not match
type SubexASTRange struct {
parts map[walk.Atom]walk.Atom
}
func (ast SubexASTRange) compileWith(next SubexState) SubexState {
return &SubexRangeState {
parts: ast.parts,
next: next,
}
}
|
