Files
honey/source/parser/parser.hon
T

318 lines
8.9 KiB
Plaintext

import "@std/mem"
import "@std/arraylist"
import "@source/diagnostics"
import "@source/lexer"
import "@source/ast"
@hide:file
SyntaxError :: enum { unexpected_token }
@hide:file
ParseError :: alias SyntaxError | mem.AllocError | diagnostics.CapacityError
@hide:file
BindingPowerScalar :: distinct u32
@hide:file
BindingPower :: struct {
left BindingPowerScalar
right BindingPowerScalar
}
@hide:file
State :: struct {
builder ast.Builder
diagnostics @mut diagnostics.Store
tokens []lexer.Token
allocator mem.Allocator
next_token usize
}
parse proc(
tokens []lexer.Token,
source []u8,
diagnostic_store @mut diagnostics.Store,
allocator mem.Allocator,
) ast.Tree ! ParseError {
state := State{
builder = ast.init_builder(allocator, source),
diagnostics = diagnostic_store,
tokens = tokens,
allocator = allocator,
next_token = 0,
}
defer ast.deinit_builder(&state.builder)
root :: try parse_package(&state)
return ast.finish(&state.builder, root)
}
@hide:file
parse_package proc(state @mut State) ast.NodeId ! ParseError {
declarations arraylist.ArrayList(ast.NodeId) := arraylist.init(state.allocator)
defer arraylist.deinit(&declarations)
skip_newlines(state)
while !next_is(state, .eof) {
declaration :: try parse_decl(state)
try arraylist.append(&declarations, declaration)
skip_newlines(state)
}
return try ast.add_package(
&state.builder,
ast.Span{ start = 0, end = u32(state.builder.source.len) },
declarations.items,
)
}
@hide:file
parse_decl proc(state @mut State) ast.NodeId ! ParseError {
if next_is(state, .ident) and next_n_is(state, 1, .proc) {
return try parse_func_decl(state)
}
return try parse_statement_decl(state)
}
@hide:file
parse_func_decl proc(state @mut State) ast.NodeId ! ParseError {
name :: try consume(state, .ident)
_ = try consume(state, .proc)
_ = try consume(state, .open_paren)
params arraylist.ArrayList(ast.NodeId) := arraylist.init(state.allocator)
defer arraylist.deinit(&params)
names arraylist.ArrayList(ast.Span) := arraylist.init(state.allocator)
defer arraylist.deinit(&names)
while !next_is(state, .close_paren) {
arraylist.clear(&names)
while true {
token :: try consume(state, .ident)
try arraylist.append(&names, token.span)
if next_is(state, .ident) break
_ = try consume(state, .comma)
}
type_id :: try parse_type(state)
type_span :: ast.builder_span(&state.builder, type_id)
for (names.items) |name_span| {
param_id :: try ast.add_param(
&state.builder,
ast.Span{ start = name_span.start, end = type_span.end },
name_span,
type_id,
)
try arraylist.append(&params, param_id)
}
if next_is(state, .comma) _ = try consume(state, .comma)
}
_ = try consume(state, .close_paren)
return_type :: try parse_type(state)
body :: try parse_block(state)
body_span :: ast.builder_span(&state.builder, body)
return try ast.add_function_decl(
&state.builder,
ast.Span{ start = name.span.start, end = body_span.end },
name.span,
return_type,
params.items,
body,
)
}
@hide:file
parse_block proc(state @mut State) ast.NodeId ! ParseError {
open :: try consume(state, .open_curly)
statements arraylist.ArrayList(ast.NodeId) := arraylist.init(state.allocator)
defer arraylist.deinit(&statements)
skip_newlines(state)
while !next_is(state, .close_curly) and !next_is(state, .eof) {
statement :: try parse_statement(state)
try arraylist.append(&statements, statement)
skip_newlines(state)
}
close :: try consume(state, .close_curly)
return try ast.add_block(
&state.builder,
ast.Span{ start = open.span.start, end = close.span.end },
statements.items,
)
}
@hide:file
parse_statement proc(state @mut State) ast.NodeId ! ParseError {
if next_is(state, .ident) return try parse_statement_decl(state)
return .unexpected_token
}
@hide:file
parse_statement_decl proc(state @mut State) ast.NodeId ! ParseError {
name :: try consume(state, .ident)
type_id ?ast.NodeId := if next_is(state, .ident)
try parse_type(state)
else
null
assignment :: try consume_either(state, &[.double_colon, .colon_equal])
initializer :: try parse_expr(state)
end :: ast.builder_span(&state.builder, initializer).end
mutability :: if (assignment.kind == .double_colon) .constant else .variable
return try ast.add_statement_decl(
&state.builder,
ast.Span{ start = name.span.start, end = end },
name.span,
type_id,
mutability,
initializer,
)
}
@hide:file
parse_type proc(state @mut State) ast.NodeId ! ParseError {
if (!next_is(state, .ident)) return .unexpected_token
token :: current(state)
state.next_token += 1
return try ast.add_identifier(&state.builder, token.span)
}
@hide:file
parse_expr proc(state @mut State) ast.NodeId ! ParseError {
return try parse_expr_bp(state, BindingPowerScalar(0))
}
@hide:file
parse_expr_bp proc(state @mut State, min_bp BindingPowerScalar) ast.NodeId ! ParseError {
token := current(state)
left := if (prefix_binding_power(token.kind)) |right_bp| {
state.next_token += 1
operand :: try parse_expr_bp(state, right_bp)
operand_span :: ast.builder_span(&state.builder, operand)
yield try ast.add_unary(
&state.builder,
ast.Span{ start = token.span.start, end = operand_span.end },
.negate,
operand,
)
} else {
yield try parse_primary(state)
}
while true {
token = current(state)
if (infix_binding_power(token.kind)) |power| {
if (power.left < min_bp) break
state.next_token += 1
right :: try parse_expr_bp(state, power.right)
left_span :: ast.builder_span(&state.builder, left)
right_span :: ast.builder_span(&state.builder, right)
left = try ast.add_binary(
&state.builder,
ast.Span{ start = left_span.start, end = right_span.end },
binary_operator(token.kind),
left,
right,
)
continue
}
break
}
return left
}
@hide:file
parse_primary proc(state @mut State) ast.NodeId ! ParseError {
token :: current(state)
match token.kind {
.int: {
state.next_token += 1
return try ast.add_literal(&state.builder, .int, token.span)
}
.float: {
state.next_token += 1
return try ast.add_literal(&state.builder, .float, token.span)
}
.string: {
state.next_token += 1
return try ast.add_literal(&state.builder, .string, token.span)
}
.ident: {
state.next_token += 1
return try ast.add_identifier(&state.builder, token.span)
}
else: return .unexpected_token
}
}
@hide:file
skip_newlines proc(state @mut State) void {
while next_is(state, .newline) state.next_token += 1
}
@hide:file
current proc(state @State) lexer.Token {
if (state.next_token >= state.tokens.len) return state.tokens[state.tokens.len - 1]
return state.tokens[state.next_token]
}
@hide:file
next_is proc(state @State, kind lexer.TokenKind) bool {
return current(state).kind == kind
}
@hide:file
next_n_is proc(state @State, count usize, kind lexer.TokenKind) bool {
index :: state.next_token + count
return index < state.tokens.len and state.tokens[index].kind == kind
}
@hide:file
consume proc(state @mut State, kind lexer.TokenKind) lexer.Token ! SyntaxError {
token :: current(state)
if (token.kind != kind) return .unexpected_token
state.next_token += 1
return token
}
@hide:file
consume_either proc(state @mut State, kinds []lexer.TokenKind) lexer.Token ! SyntaxError {
token :: current(state)
for (kinds) |kind| if token.kind == kind {
state.next_token += 1
return token
}
return .unexpected_token
}
@hide:file
prefix_binding_power proc(kind lexer.TokenKind) ?BindingPowerScalar {
return match kind {
.minus: BindingPowerScalar(30)
else: null
}
}
@hide:file
infix_binding_power proc(kind lexer.TokenKind) ?BindingPower {
return match kind {
.plus, .minus: BindingPower{ left = BindingPowerScalar(10), right = BindingPowerScalar(11) }
.star, .slash: BindingPower{ left = BindingPowerScalar(20), right = BindingPowerScalar(21) }
else: null
}
}
@hide:file
binary_operator proc(kind lexer.TokenKind) ast.BinaryOperator {
return match kind {
.plus: .add
.minus: .subtract
.star: .multiply
.slash: .divide
else: unreachable
}
}