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Precedence tuning (#153)
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1. fixes several corner cases, such as:
```nushell
# empty list
[,,,]

# record with leading comment
# previously parsed as closure
{
# foo
echo : 1
}
```
2. generalizes `general_body_rule` to cover more rules within the same
pattern
3. makes anonymous tokens more friendly for topiary to format
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@blindFS
blindFS authored Nov 22, 2024
1 parent fa2f2d0 commit 54936b0
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Showing 7 changed files with 276,555 additions and 273,311 deletions.
185 changes: 99 additions & 86 deletions grammar.js
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Original file line number Diff line number Diff line change
Expand Up @@ -24,21 +24,22 @@ module.exports = grammar({

conflicts: ($) => [
[$._binary_predicate_parenthesized],
[$._block_body, $.record_body, $.val_closure],
[$._block_body, $.shebang],
[$._block_body, $.val_closure],
[$._expression_parenthesized, $._expr_binary_expression_parenthesized],
[$._match_pattern_list, $.val_list],
[$._match_pattern_record, $.val_record],
[$._match_pattern_record_variable, $._value],
[$._match_pattern_value, $._value],
[$._parenthesized_body],
[$._block_body, $.record_body],
[$._block_body, $.shebang],
[$._val_number_decimal],
[$.block, $.val_closure],
[$.block, $.val_record],
[$.ctrl_if_parenthesized],
[$.ctrl_match],
[$.ctrl_try_parenthesized],
[$.expr_binary_parenthesized],
[$.list_body, $.val_table],
[$.parameter, $.param_type, $.param_value],
[$.pipeline],
[$.pipeline_parenthesized],
Expand All @@ -53,22 +54,16 @@ module.exports = grammar({

...block_body_rules(),

// Because everything inside of the parentheses are treated as if they were written together,
// terminator must be semicolon.
...parenthesized_body_rules(),

_block_body: ($) =>
choice(
seq(
repeat($._terminator),
prec.right(
repeat(seq($._block_body_statement, repeat1($._terminator))),
),
$._block_body_statement,
repeat($._terminator),
),
// empty blocks
repeat1($._terminator),
general_body_rules(
"",
$._block_body_statement,
$._terminator,
null,
null,
$._terminator,
),

/// Identifiers
Expand Down Expand Up @@ -188,7 +183,9 @@ module.exports = grammar({
_multiple_types: ($) =>
seq(
BRACK().open_brack,
optional(general_body_rules("", "_one_type", "_entry_separator")($)),
optional(
general_body_rules("", $._one_type, $._entry_separator, $._newline),
),
BRACK().close_brack,
),

Expand Down Expand Up @@ -441,9 +438,15 @@ module.exports = grammar({
"scrutinee",
choice($._item_expression, alias($.unquoted, $.val_string)),
),
open_brace(),
optional(general_body_rules("", "match_arm", "_entry_separator")($)),
optional($.default_arm),
BRACK().open_brace,
optional(
general_body_rules(
"",
choice($.match_arm, $.default_arm),
$._entry_separator,
$._newline,
),
),
BRACK().close_brace,
),

Expand All @@ -459,7 +462,6 @@ module.exports = grammar({
field("default_pattern", PUNC().underscore),
PUNC().fat_arrow,
field("expression", $._match_expression),
repeat($._entry_separator),
),

_match_expression: ($) =>
Expand Down Expand Up @@ -531,7 +533,7 @@ module.exports = grammar({

_match_pattern_record: ($) =>
seq(
open_brace(),
BRACK().open_brace,
repeat(
field(
"entry",
Expand Down Expand Up @@ -679,15 +681,20 @@ module.exports = grammar({
seq(
BRACK().open_brack,
optional(
general_body_rules("cmd", "_command_name", "_entry_separator")($),
general_body_rules(
"cmd",
$._command_name,
$._entry_separator,
$._newline,
),
),
BRACK().close_brack,
),

/// Block

block: ($) =>
seq(open_brace(), optional($._block_body), BRACK().close_brace),
seq(BRACK().open_brace, optional($._block_body), BRACK().close_brace),

_blosure: ($) => choice(prec.dynamic(10, $.block), $.val_closure),

Expand Down Expand Up @@ -828,22 +835,16 @@ module.exports = grammar({
),

_parenthesized_body: ($) =>
choice(
seq(
repeat($._terminator),
repeat(
seq(
$._block_body_statement_parenthesized,
// at least one ;
repeat1(seq(repeat($._newline), PUNC().semicolon)),
),
),
general_body_rules(
"",
$._block_body_statement_parenthesized,
$._terminator,
null,
[
repeat1(seq(repeat($._newline), PUNC().semicolon)),
repeat($._newline),
$._block_body_statement_parenthesized,
repeat($._terminator),
),
// empty body
repeat1($._terminator),
],
$._terminator,
),

val_range: _range_rule(false),
Expand Down Expand Up @@ -1091,7 +1092,15 @@ module.exports = grammar({
alias($._spread_parenthesized, $.expr_parenthesized),
),

list_body: general_body_rules("entry", "val_entry", "_entry_separator"),
list_body: ($) =>
general_body_rules(
"entry",
$.val_entry,
$._entry_separator,
$._newline,
null,
choice($._newline, PUNC().comma),
),

val_entry: ($) =>
prec(
Expand All @@ -1112,7 +1121,7 @@ module.exports = grammar({

val_record: ($) =>
seq(
open_brace(),
BRACK().open_brace,
optional($.record_body),
BRACK().close_brace,
optional($.cell_path),
Expand All @@ -1133,11 +1142,13 @@ module.exports = grammar({
alias($._spread_parenthesized, $.expr_parenthesized),
),

record_body: general_body_rules(
"entry",
"record_entry",
"_entry_separator",
),
record_body: ($) =>
general_body_rules(
"entry",
$.record_entry,
$._entry_separator,
$._newline,
),

_entry_separator: (_$) =>
token(prec(PREC().higher, choice(PUNC().comma, /\s/))),
Expand Down Expand Up @@ -1194,15 +1205,19 @@ module.exports = grammar({
seq(
BRACK().open_brack,
repeat($._newline),
field("head", seq($.val_list, $._table_head_separator)),
optional(general_body_rules("row", "val_list", "_entry_separator")($)),
field("head", $.val_list),
alias($._table_head_separator, PUNC().semicolon),
optional(
general_body_rules("row", $.val_list, $._entry_separator, $._newline),
),
BRACK().close_brack,
optional($.cell_path),
),

val_closure: ($) =>
seq(
open_brace(),
BRACK().open_brace,
repeat($._newline),
optional(field("parameters", $.parameter_pipes)),
$._block_body,
BRACK().close_brace,
Expand Down Expand Up @@ -1338,40 +1353,47 @@ function _identifier_rules(immediate) {
}

/**
* for rules of repeated pattern that require separator in-between
* e.g. list, record, blocks
* @param {string} field_name
* @param {string} entry
* @param {string} separator
* @param {any} entry base build block
* @param {any} separator separator between entries
* @param {any} preceding separator before first entry, defaults to separator
* @param {array} alt_sep array of rules to override default separator
* @param {any} empty_unit optional for empty body
*/
function general_body_rules(field_name, entry, separator) {
return (/** @type {{ [x: string]: RuleOrLiteral; }} */ $) => {
const field_entry =
field_name.length == 0 ? $[entry] : field(field_name, $[entry]);
return prec(
PREC().higher,
seq(
repeat($._newline),
// Normal entries MUST have a separator
repeat(seq(field_entry, repeat1($[separator]))),
// Final entry may or may not have separator
seq(field_entry, repeat($[separator])),
),
);
};
function general_body_rules(
field_name,
entry,
separator,
preceding = null,
alt_sep = null,
empty_unit = null,
) {
const field_entry = field_name.length == 0 ? entry : field(field_name, entry);
const prec_sep = preceding || separator;
// Normal entries MUST have a separator
const sep_array = alt_sep || [repeat1(separator)];
const rule = prec(
PREC().higher,
seq(
repeat(prec_sep),
repeat(seq(field_entry, ...sep_array)),
field_entry,
// Final entry may or may not have separator
repeat(separator),
),
);
return empty_unit ? choice(repeat1(empty_unit), rule) : rule;
}

/**
* @param {string} suffix
* @param {{ (_$: any): string; (_$: any): ChoiceRule; (arg0: any): RuleOrLiteral; }} terminator
*/
function parenthesized_body_rules() {
return {
..._block_body_rules("_parenthesized"),

/// pipeline

pipeline_parenthesized: (
/** @type {{ pipe_element_parenthesized: RuleOrLiteral; pipe_element: string; }} */ $,
) =>
pipeline_parenthesized: ($) =>
seq(
repeat(
seq(
Expand All @@ -1385,17 +1407,13 @@ function parenthesized_body_rules() {
};
}

/**
* @param {string} suffix
* @param {{ ($: { _terminator: any; }): any; ($: { _terminator: RuleOrLiteral; }): ChoiceRule; (arg0: any): RuleOrLiteral; }} terminator
*/
function block_body_rules() {
return {
..._block_body_rules(""),

/// pipeline

pipeline: (/** @type {any} */ $) =>
pipeline: ($) =>
seq(
repeat(seq($.pipe_element, $._pipe_separator, optional($._newline))),
$.pipe_element,
Expand Down Expand Up @@ -1574,7 +1592,7 @@ function _command_rule(parenthesized) {
field("head", seq(optional(PUNC().caret), $.cmd_identifier)),
field("head", seq(PUNC().caret, $._stringish)),
),
prec.dynamic(10, repeat(seq(sep, optional($._cmd_arg)))),
repeat(seq(sep, optional($._cmd_arg))),
),
);
};
Expand Down Expand Up @@ -1825,6 +1843,7 @@ function _range_rule(anonymous, with_end_decimal = false) {
}

/**
* For expressions like: foo('bar')baz
* @param {string} type
*/
function _unquoted_with_expr_rule(type) {
Expand Down Expand Up @@ -2052,20 +2071,14 @@ function BRACK() {
};
}

// group open_brace and following whitespace/newline together
// so they won't participate in conflicts resolving between record and block
function open_brace() {
return alias(token(seq(BRACK().open_brace, /\s*/)), BRACK().open_brace);
}

/**
* group operator and its preceding/succeeding whitespace/newline
* @param {string} opr
* @param {boolean} parenthesized
*/
function operator_with_separator(opr, parenthesized) {
const sep = parenthesized ? choice(/[ \t]/, /\r?\n/) : /[ \t]/;
return alias(token(seq(repeat1(sep), opr, repeat1(sep))), opr);
return alias(token(seq(sep, opr, sep)), opr);
}

/**
Expand Down
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