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mjambonNathan Brahmsmaxbrunsfeld
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Optional chaining (#137)
* Add partial support for optional chaining: a?.b and a?.[b] but not f?.(x). * Update generated files * Undo experimental change * Add safe dereference for function calls * fixup! Add safe dereference for function calls * Add failing test case for optional chaining using a proper '?.' token for optional calls. * Simplify parsing of new_expression, avoid ?.( token Co-authored-by: Martin Jambon <Martin Jambon> Co-authored-by: Nathan Brahms <[email protected]> Co-authored-by: Max Brunsfeld <[email protected]>
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lines changed

‎grammar.js‎

Lines changed: 15 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -20,7 +20,7 @@ const PREC = {
2020
NEG: 10,
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INC: 11,
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CALL: 12,
23-
NEW: 13,
23+
NEW: 12,
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MEMBER: 14
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};
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@@ -75,6 +75,7 @@ module.exports = grammar({
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[$.assignment_pattern, $.assignment_expression],
7676
[$.computed_property_name, $.array],
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[$._for_header, $._expression],
78+
[$.call_expression, $.new_expression],
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],
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8081
word: $ => $.identifier,
@@ -625,18 +626,19 @@ module.exports = grammar({
625626
),
626627

627628
call_expression: $ => prec(PREC.CALL, seq(
628-
field('function', choice($._expression, $.super, $.function)),
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field('function', $._expression),
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optional('?.'),
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field('arguments', choice($.arguments, $.template_string))
630632
)),
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632-
new_expression: $ => prec.right(PREC.NEW, seq(
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new_expression: $ => prec(PREC.NEW, seq(
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'new',
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field('constructor', $._constructable_expression),
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field('arguments', optional($.arguments))
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field('constructor', $._expression),
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field('arguments', optional(prec.dynamic(1, $.arguments)))
636638
)),
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638640
_constructable_expression: $ => choice(
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// Primary Expression
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$.super,
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$.this,
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$.identifier,
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alias($._reserved_identifier, $.identifier),
@@ -668,19 +670,17 @@ module.exports = grammar({
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),
669671

670672
member_expression: $ => prec(PREC.MEMBER, seq(
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field('object', choice(
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$._expression,
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$.identifier,
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$.super,
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alias($._reserved_identifier, $.identifier)
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)),
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'.',
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field('object', $._expression),
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choice('.', '?.'),
678675
field('property', alias($.identifier, $.property_identifier))
679676
)),
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681678
subscript_expression: $ => prec.right(PREC.MEMBER, seq(
682-
field('object', choice($._expression, $.super)),
683-
'[', field('index', $._expressions), ']'
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field('object', $._expression),
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optional('?.'),
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'[',
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field('index', $._expressions),
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']'
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)),
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686686
_lhs_expression: $ => choice(

‎src/grammar.json‎

Lines changed: 62 additions & 61 deletions
Original file line numberDiff line numberDiff line change
@@ -2688,23 +2688,22 @@
26882688
"type": "FIELD",
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"name": "function",
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"content": {
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"type": "CHOICE",
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"members": [
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{
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"type": "SYMBOL",
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"name": "_expression"
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},
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{
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"type": "SYMBOL",
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"name": "super"
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},
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{
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"type": "SYMBOL",
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"name": "function"
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}
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]
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"type": "SYMBOL",
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"name": "_expression"
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}
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},
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{
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"type": "CHOICE",
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"members": [
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{
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"type": "STRING",
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"value": "?."
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},
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{
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"type": "BLANK"
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}
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]
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},
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{
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"type": "FIELD",
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"name": "arguments",
@@ -2726,8 +2725,8 @@
27262725
}
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},
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"new_expression": {
2729-
"type": "PREC_RIGHT",
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"value": 13,
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"type": "PREC",
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"value": 12,
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"content": {
27322731
"type": "SEQ",
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"members": [
@@ -2740,7 +2739,7 @@
27402739
"name": "constructor",
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"content": {
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"type": "SYMBOL",
2743-
"name": "_constructable_expression"
2742+
"name": "_expression"
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}
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},
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{
@@ -2750,8 +2749,12 @@
27502749
"type": "CHOICE",
27512750
"members": [
27522751
{
2753-
"type": "SYMBOL",
2754-
"name": "arguments"
2752+
"type": "PREC_DYNAMIC",
2753+
"value": 1,
2754+
"content": {
2755+
"type": "SYMBOL",
2756+
"name": "arguments"
2757+
}
27552758
},
27562759
{
27572760
"type": "BLANK"
@@ -2765,6 +2768,10 @@
27652768
"_constructable_expression": {
27662769
"type": "CHOICE",
27672770
"members": [
2771+
{
2772+
"type": "SYMBOL",
2773+
"name": "super"
2774+
},
27682775
{
27692776
"type": "SYMBOL",
27702777
"name": "this"
@@ -2887,35 +2894,22 @@
28872894
"type": "FIELD",
28882895
"name": "object",
28892896
"content": {
2890-
"type": "CHOICE",
2891-
"members": [
2892-
{
2893-
"type": "SYMBOL",
2894-
"name": "_expression"
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},
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{
2897-
"type": "SYMBOL",
2898-
"name": "identifier"
2899-
},
2900-
{
2901-
"type": "SYMBOL",
2902-
"name": "super"
2903-
},
2904-
{
2905-
"type": "ALIAS",
2906-
"content": {
2907-
"type": "SYMBOL",
2908-
"name": "_reserved_identifier"
2909-
},
2910-
"named": true,
2911-
"value": "identifier"
2912-
}
2913-
]
2897+
"type": "SYMBOL",
2898+
"name": "_expression"
29142899
}
29152900
},
29162901
{
2917-
"type": "STRING",
2918-
"value": "."
2902+
"type": "CHOICE",
2903+
"members": [
2904+
{
2905+
"type": "STRING",
2906+
"value": "."
2907+
},
2908+
{
2909+
"type": "STRING",
2910+
"value": "?."
2911+
}
2912+
]
29192913
},
29202914
{
29212915
"type": "FIELD",
@@ -2943,19 +2937,22 @@
29432937
"type": "FIELD",
29442938
"name": "object",
29452939
"content": {
2946-
"type": "CHOICE",
2947-
"members": [
2948-
{
2949-
"type": "SYMBOL",
2950-
"name": "_expression"
2951-
},
2952-
{
2953-
"type": "SYMBOL",
2954-
"name": "super"
2955-
}
2956-
]
2940+
"type": "SYMBOL",
2941+
"name": "_expression"
29572942
}
29582943
},
2944+
{
2945+
"type": "CHOICE",
2946+
"members": [
2947+
{
2948+
"type": "STRING",
2949+
"value": "?."
2950+
},
2951+
{
2952+
"type": "BLANK"
2953+
}
2954+
]
2955+
},
29592956
{
29602957
"type": "STRING",
29612958
"value": "["
@@ -4514,7 +4511,7 @@
45144511
},
45154512
{
45164513
"type": "PATTERN",
4517-
"value": "[^*]*\\*+([^\\/*][^*]*\\*+)*"
4514+
"value": "[^*]*\\*+([^/*][^*]*\\*+)*"
45184515
},
45194516
{
45204517
"type": "STRING",
@@ -4676,7 +4673,7 @@
46764673
},
46774674
{
46784675
"type": "PATTERN",
4679-
"value": "[^\\/\\\\\\[\\n]"
4676+
"value": "[^/\\\\\\[\\n]"
46804677
}
46814678
]
46824679
}
@@ -5185,13 +5182,13 @@
51855182
"members": [
51865183
{
51875184
"type": "PATTERN",
5188-
"value": "[^\\x00-\\x1F\\s0-9:;`\"'@#.,|^&<=>+\\-*\\/\\\\%?!~()\\[\\]{}\\uFEFF\\u2060\\u200B\\u00A0]|\\\\u[0-9a-fA-F]{4}|\\\\u\\{[0-9a-fA-F]+\\}"
5185+
"value": "[^\\x00-\\x1F\\s0-9:;`\"'@#.,|^&<=>+\\-*/\\\\%?!~()\\[\\]{}\\uFEFF\\u2060\\u200B\\u00A0]|\\\\u[0-9a-fA-F]{4}|\\\\u\\{[0-9a-fA-F]+\\}"
51895186
},
51905187
{
51915188
"type": "REPEAT",
51925189
"content": {
51935190
"type": "PATTERN",
5194-
"value": "[^\\x00-\\x1F\\s:;`\"'@#.,|^&<=>+\\-*\\/\\\\%?!~()\\[\\]{}\\uFEFF\\u2060\\u200B\\u00A0]|\\\\u[0-9a-fA-F]{4}|\\\\u\\{[0-9a-fA-F]+\\}"
5191+
"value": "[^\\x00-\\x1F\\s:;`\"'@#.,|^&<=>+\\-*/\\\\%?!~()\\[\\]{}\\uFEFF\\u2060\\u200B\\u00A0]|\\\\u[0-9a-fA-F]{4}|\\\\u\\{[0-9a-fA-F]+\\}"
51955192
}
51965193
}
51975194
]
@@ -5930,6 +5927,10 @@
59305927
[
59315928
"_for_header",
59325929
"_expression"
5930+
],
5931+
[
5932+
"call_expression",
5933+
"new_expression"
59335934
]
59345935
],
59355936
"externals": [

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