Files
vim-polyglot/autoload/smt2/parser.vim
2023-10-10 23:21:12 +11:00

357 lines
12 KiB
VimL

if polyglot#init#is_disabled(expand('<sfile>:p'), 'smt2', 'autoload/smt2/parser.vim')
finish
endif
vim9script
const debug = false
set maxfuncdepth=100000000 # SMT files tend to be highly nested
# TODO: Retry iterative parsing now that we have a scanner and simpler grammar
# TODO: Refer to token kind by name, e.g. token_comment instead of 8
# TODO: Change Ast.kind type from string to enum/number?
# ------------------------------------------------------------------------------
# AST nodes
#
# Note: pos_from, pos_to and contains_comment allow for a fast FitsOneLine(ast)
# function in the formatter.
# Here, pos_from and pos_to refer to indices of characters -- not tokens.
# ------------------------------------------------------------------------------
def Ast(kind: string, value: any, pos_from: number, pos_to: number, contains_comment: bool, scanner: dict<any>): dict<any>
# User-facing functionality wants start/end line and column -- not positions
def CalcCoords(): list<dict<number>>
const from = scanner.calcCoord(pos_from)
# If expression ends at end of line, pos_to will be in next line.
# That's undesired. Stay in the actual last line.
var to = scanner.calcCoord(pos_to - 1)
to.col += 1
return [from, to]
enddef
return {kind: kind, value: value, pos_from: pos_from, pos_to: pos_to, contains_comment: contains_comment, CalcCoords: CalcCoords}
enddef
def FileAst(paragraphs: list<dict<any>>, pos_from: number, pos_to: number, scanner: dict<any>): dict<any>
var contains_comment = false
for paragraph in paragraphs
if paragraph.contains_comment
contains_comment = true
break
endif
endfor
return Ast('File', paragraphs, pos_from, pos_to, contains_comment, scanner)
enddef
def ParagraphAst(exprs: list<dict<any>>, pos_from: number, pos_to: number, scanner: dict<any>): dict<any>
var contains_comment = false
for expr in exprs
if expr.contains_comment
contains_comment = true
break
endif
endfor
return Ast('Paragraph', exprs, pos_from, pos_to, contains_comment, scanner)
enddef
def SExprAst(exprs: list<dict<any>>, pos_from: number, pos_to: number, scanner: dict<any>): dict<any>
var contains_comment = false
for expr in exprs
if expr.contains_comment
contains_comment = true
break
endif
endfor
return Ast('SExpr', exprs, pos_from, pos_to, contains_comment, scanner)
enddef
def AtomAst(token: dict<any>, scanner: dict<any>): dict<any>
return Ast('Atom', token, token.pos, token.pos + len(token.lexeme), token.kind == 8, scanner)
enddef
def PrintAst(ast: dict<any>, indent = 0)
const coords = ast.CalcCoords()
echo printf("[%5d-%-5d) [%4d:%-3d-%4d:%-3d) %s[%s] ",
ast.pos_from, ast.pos_to,
coords[0].line, coords[0].col,
coords[1].line, coords[1].col,
repeat(' ', indent * 2),
ast.kind)
if ast.kind ==# 'Atom'
echon ast.value.lexeme
elseif ast.kind ==# 'SExpr'
for v in ast.value
call PrintAst(v, indent + 1)
endfor
elseif ast.kind ==# 'Paragraph'
for v in ast.value
call PrintAst(v, indent + 1)
endfor
elseif ast.kind ==# 'File'
for v in ast.value
call PrintAst(v, indent + 1)
endfor
endif
enddef
# ------------------------------------------------------------------------------
# Grammar
# ------------------------------------------------------------------------------
# File ::= Paragraph+
# Paragraph ::= Expr+ EndOfParagraph
# Expr ::= SExpr | Atom
# SExpr ::= '(' Expr* ')'
# ------------------------------------------------------------------------------
# LParen
# ------------------------------------------------------------------------------
def AtStartOfLParen(scanner: dict<any>): bool
return scanner.cur_token.kind == 0 # token_lparen
enddef
def ParseLParen(scanner: dict<any>): dict<any>
if debug
scanner->smt2#scanner#Enforce(scanner->AtStartOfLParen(),
"ParseLParen called but not at start of LParen",
scanner.cur_token.pos)
endif
const token = scanner.cur_token
scanner->smt2#scanner#NextToken()
return token
enddef
# ------------------------------------------------------------------------------
# RParen
# ------------------------------------------------------------------------------
def AtStartOfRParen(scanner: dict<any>): bool
return scanner.cur_token.kind == 1 # token_rparen
enddef
def ParseRParen(scanner: dict<any>): dict<any>
if debug
scanner->smt2#scanner#Enforce(scanner->AtStartOfRParen(),
"ParseRParen called but not at start of RParen",
scanner.cur_token.pos)
endif
const token = scanner.cur_token
scanner->smt2#scanner#NextToken()
return token
enddef
# ------------------------------------------------------------------------------
# Atom
# ------------------------------------------------------------------------------
def AtStartOfAtom(scanner: dict<any>): bool
return 2 <= scanner.cur_token.kind && scanner.cur_token.kind <= 8
enddef
def ParseAtom(scanner: dict<any>): dict<any>
if debug
scanner->smt2#scanner#Enforce(scanner->AtStartOfAtom(),
"ParseAtom called but not at start of Atom",
scanner.cur_token.pos)
endif
const ast = AtomAst(scanner.cur_token, scanner)
scanner->smt2#scanner#NextToken()
return ast
enddef
# ------------------------------------------------------------------------------
# Expr
# ------------------------------------------------------------------------------
def AtStartOfExpr(scanner: dict<any>): bool
return scanner->AtStartOfSExpr() || scanner->AtStartOfAtom()
enddef
def ParseExpr(scanner: dict<any>): dict<any>
if debug
scanner->smt2#scanner#Enforce(scanner->AtStartOfExpr(),
"ParseExpr called but not at start of Expr",
scanner.cur_token.pos)
endif
if scanner->AtStartOfSExpr()
return scanner->ParseSExpr()
endif
return scanner->ParseAtom()
enddef
# ------------------------------------------------------------------------------
# SExpr
# ------------------------------------------------------------------------------
const AtStartOfSExpr = funcref(AtStartOfLParen)
def ParseSExpr(scanner: dict<any>): dict<any>
const pos_from = scanner.cur_token.pos
if debug
scanner->smt2#scanner#Enforce(scanner->AtStartOfSExpr(),
"ParseSExpr called but not at start of SExpr",
pos_from)
endif
scanner->ParseLParen()
# Expr*
var exprs: list<dict<any>>
while scanner->AtStartOfExpr()
exprs->add(scanner->ParseExpr())
endwhile
scanner->smt2#scanner#Enforce(scanner->AtStartOfRParen(),
printf("Expected RParen but got %s", scanner.cur_token.kind->smt2#scanner#TokenKind2Str()),
scanner.cur_token.pos)
const end_token = scanner->ParseRParen()
const pos_to = end_token.pos + 1
return SExprAst(exprs, pos_from, pos_to, scanner)
enddef
# ------------------------------------------------------------------------------
# Paragraph
# ------------------------------------------------------------------------------
def ParseParagraph(scanner: dict<any>): dict<any>
const pos_from = scanner.cur_token.pos
# Expr+
scanner->smt2#scanner#Enforce(scanner->AtStartOfExpr(),
printf("Expected Expr but got %s", scanner.cur_token.kind->smt2#scanner#TokenKind2Str()),
pos_from)
var exprs = [scanner->ParseExpr()]
while scanner->AtStartOfExpr() && !scanner.at_new_paragraph
exprs->add(scanner->ParseExpr())
endwhile
const pos_to = exprs[-1].pos_to
return ParagraphAst(exprs, pos_from, pos_to, scanner)
enddef
# ------------------------------------------------------------------------------
# File
# ------------------------------------------------------------------------------
def ParseFile(scanner: dict<any>): dict<any>
const pos_from = scanner.cur_token.pos
var paragraphs = []
while scanner.cur_token.kind != 9 # token_eof
const ast = scanner->ParseParagraph()
paragraphs->add(ast)
endwhile
const pos_to = empty(paragraphs) ? pos_from : paragraphs[-1].pos_to
return FileAst(paragraphs, pos_from, pos_to, scanner)
enddef
# ------------------------------------------------------------------------------
# Auxiliary
#
# TODO: MoveTo* functions rely on local search instead of proper (but slow)
# scanning of the whole file and may be incorrect in corner cases.
# Consider tweaking.
# ------------------------------------------------------------------------------
# Returns true if successful, i.e. on move to '(' of outermost SExpr
def MoveToOutermostSExpr(): bool
var cur_pos = getpos('.')
while true
silent! normal! [(
const new_pos = getpos('.')
if cur_pos == new_pos
break
else
cur_pos = new_pos
endif
endwhile
const cur_char = getline('.')[charcol('.') - 1]
return cur_char == '('
enddef
def CursorInSExpr(): bool
const cursor = getpos('.')
silent! normal! [(
const res = cursor != getpos('.')
call setpos('.', cursor)
return res
enddef
def MoveToStartOfCurrentParagraph()
# Empty (or whitespace) lines outside of S-expressions separate paragraphs.
# Nothing to do if cursor is already at such a line.
if !(getline('.')->trim()->empty() && !CursorInSExpr())
# Move backwards until an empty line that is not in an SExpr is found,
# or -- if there is none -- to the first line of the file
while true
const empty_line = search('\m\C^\s*$', 'b', 1)
if !CursorInSExpr()
break
elseif empty_line == 0
cursor(1, 1)
break
endif
endwhile
endif
enddef
# ------------------------------------------------------------------------------
# Public functions
# ------------------------------------------------------------------------------
def smt2#parser#ParseCurrentParagraph(): dict<any>
const cursor = getpos('.')
MoveToStartOfCurrentParagraph()
const from = getpos('.')
call setpos('.', cursor)
# source = [paragraph of outermost SExpr, EOF]
# Note: This is needed since `silent! normal! {` is not guaranteed to jump
# to the start of the paragraph, e.g. if newlines occur in between.
const lines_to_format = getline(from[1], '$')
const source = join(lines_to_format, "\n")
var scanner = smt2#scanner#Scanner(source, from[1], from[2])
const ast = scanner->ParseParagraph()
if debug | ast->PrintAst() | endif
return ast
enddef
def smt2#parser#ParseOutermostSExpr(): dict<any>
const cursor = getpos('.')
if ! MoveToOutermostSExpr()
throw "Cursor is not in an S-expression!"
endif
const from = getpos('.')
call setpos('.', cursor)
# source = [start of outermost SExpr, EOF]
# Note: This is needed since `silent! normal! %` is not guaranteed to jump
# to the matching ')', e.g. if an unmatched '(' occurs in a comment.
const lines_to_format = getline(from[1], '$')
const source = join(lines_to_format, "\n")
var scanner = smt2#scanner#Scanner(source, from[1], from[2])
const ast = scanner->ParseSExpr()
if debug | ast->PrintAst() | endif
return ast
enddef
def smt2#parser#ParseFile(): dict<any>
const cursor = getpos('.')
cursor(1, 1)
const first_non_empty_line = search('.')
call setpos('.', cursor)
# source = [first non-empty line, EOF]
const source = join(getline(first_non_empty_line, '$'), "\n")
var scanner = smt2#scanner#Scanner(source, first_non_empty_line)
const ast = scanner->ParseFile()
if debug | ast->PrintAst() | endif
return ast
enddef