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RakuAST: make statement-control prote more readable
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@lizmat
lizmat committed Aug 18, 2023
1 parent 5ef70c6 commit 0ad03b5
Showing 1 changed file with 79 additions and 53 deletions.
132 changes: 79 additions & 53 deletions src/Raku/Grammar.nqp
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Original file line number Diff line number Diff line change
Expand Up @@ -766,7 +766,8 @@ grammar Raku::Grammar is HLL::Grammar does Raku::Common {
[
| <label> <statement>
| <statement-control>
| <EXPR> :dba('statement end')
| <EXPR>
:dba('statement end')
[
|| <?MARKED('endstmt')>
|| :dba('statement modifier')
Expand Down Expand Up @@ -807,14 +808,9 @@ grammar Raku::Grammar is HLL::Grammar does Raku::Common {
|| <?before [ # OR looks like leaking into next
for | if | for | given | loop | repeat | when | while
] » >
{
$/.'!clear_highwater'();
$/.typed_panic( 'X::Syntax::Confused',
reason => "Missing semicolon" );
}
|| { # OR give up
$/.typed_panic('X::Syntax::Confused')
}
{ $/.'!clear_highwater'() }
<.typed_panic: 'X::Syntax::Confused', reason => "Missing semicolon">
|| <.typed_panic: 'X::Syntax::Confused'> # OR give up
}
# Helper token to match the start of a pointy block
Expand Down Expand Up @@ -963,33 +959,41 @@ grammar Raku::Grammar is HLL::Grammar does Raku::Common {
# Handle "if" / "with"
rule statement-control:sym<if> {
$<sym>=[if|with]<.kok> {}
$<sym>=[if|with]<.kok>
{}
:my $*GOAL := '{';
:my $*BORG := {};
<condition=.EXPR>
<then=.pointy-block>
[
[
| 'else'\h*'if' <.typed_panic: 'X::Syntax::Malformed::Elsif'>
| 'elif' { $/.typed_panic('X::Syntax::Malformed::Elsif', what => "elif") }
| $<sym>='elsif' <condition=.EXPR> <then=.pointy-block>
| $<sym>='orwith' <condition=.EXPR> <then=.pointy-block>
]
<condition=.EXPR> # initial condition
<then=.pointy-block> # initial body
[ # any elsifs/orwiths
[
| else\h*if
<.typed_panic: 'X::Syntax::Malformed::Elsif'>
| elif
<.typed_panic: 'X::Syntax::Malformed::Elsif', :what<elif> >
| $<sym>=[elsif|orwith]
<condition=.EXPR>
<then=.pointy-block>
]
]*
{}
[
'else'
else
<else=.pointy-block>
]?
}
# Handle "for"
rule statement-control:sym<for> {
<sym><.kok> {}
[ <?before 'my'? '$'\w+\s+'(' >
<.typed_panic: 'X::Syntax::P5'> ]?
[ <?before '(' <.EXPR>? ';' <.EXPR>? ';' <.EXPR>? ')' >
<.obs('C-style "for (;;)" loop', '"loop (;;)"')> ]?
[
<?before 'my'? '$'\w+\s+'('>
<.typed_panic: 'X::Syntax::P5'>
]?
[
<?before '(' <.EXPR>? ';' <.EXPR>? ';' <.EXPR>? ')'>
<.obs('C-style "for (;;)" loop', '"loop (;;)"')>
]?
:my $*GOAL := '{';
:my $*BORG := {};
<EXPR>
Expand All @@ -998,31 +1002,38 @@ grammar Raku::Grammar is HLL::Grammar does Raku::Common {
# Handle repeat ... while | until
rule statement-control:sym<repeat> {
<sym><.kok> {}
<sym><.kok>
{}
[
| $<wu>=[while|until]<.kok>
:my $*GOAL := '{';
:my $*BORG := {};
<EXPR>
<pointy-block>
| <pointy-block>
[$<wu>=['while'|'until']<.kok> || <.missing('"while" or "until"')>]
<EXPR>
| $<wu>=[while|until]<.kok>
:my $*GOAL := '{';
:my $*BORG := {};
<EXPR>
<pointy-block>
| <pointy-block>
[
$<wu>=['while'|'until']<.kok>
|| <.missing('"while" or "until"')>
]
<EXPR>
]
}
# Handle whenever inside supply / react
rule statement-control:sym<whenever> {
<sym><.kok>
[
|| <?{ nqp::getcomp('Raku').language_revision == 1
|| $*WHENEVER-COUNT >= 0 }>
|| <.typed_panic('X::Comp::WheneverOutOfScope')>
|| <?{
nqp::getcomp('Raku').language_revision == 1
|| $*WHENEVER-COUNT >= 0
}>
|| <.typed_panic: 'X::Comp::WheneverOutOfScope'>
]
{ $*WHENEVER-COUNT++ }
:my $*GOAL := '{';
:my $*BORG := {};
<EXPR> <pointy-block>
<EXPR>
<pointy-block>
}
# Handle basic loop / C-style loop
Expand All @@ -1032,35 +1043,50 @@ grammar Raku::Grammar is HLL::Grammar does Raku::Common {
[
:my $exprs := 0;
'('
[ <e1=.EXPR>? {$exprs := 1 if $<e1>}
[ ';' <e2=.EXPR>? {$exprs := 2}
[ ';' <e3=.EXPR>? {$exprs := 3}
]? ]? ]? # succeed anyway, this will leave us with a nice cursor
[
|| <?{ $exprs == 3 }> ')'
|| <?before ')'>
[
|| <?{ $exprs == 0 }>
<.malformed("loop spec (expected 3 semicolon-separated expressions)")>
|| <.malformed("loop spec (expected 3 semicolon-separated expressions but got {$exprs})")>
]
|| <?before ‘;’>
<.malformed('loop spec (expected 3 semicolon-separated expressions but got more)')>
|| <.malformed('loop spec')>
<e1=.EXPR>? { $exprs := 1 if $<e1> }
[
';' <e2=.EXPR>? { $exprs := 2 }
[
';' <e3=.EXPR>? { $exprs := 3 }
]?
]?
]? # succeed anyway, this will leave us with a nice cursor
[
|| <?{ $exprs == 3 }> ')'
|| <?before ')'>
[
|| <?{ $exprs == 0 }>
<.malformed:
"loop spec (expected 3 semicolon-separated expressions)"
>
|| <.malformed:
"loop spec (expected 3 semicolon-separated expressions but got {$exprs})"
>
]
|| <?before ‘;’>
<.malformed:
"loop spec (expected 3 semicolon-separated expressions but got more)"
>
|| <.malformed: "loop spec">
]
]?
<block>
}
# handle people coming from Perl
rule statement-control:sym<foreach> {
<sym><.end-keyword> <.obs("'foreach'", "'for'")>
<sym><.end-keyword>
<.obs: "'foreach'", "'for'">
}
# Not really control statements, more grammar tweaks
rule statement-control:sym<also> {
<sym><.kok>
[ <trait>+ || <.panic: "No valid trait found after 'also'"> ]
[
<trait>+
|| <.panic: "No valid trait found after 'also'">
]
}
#-------------------------------------------------------------------------------
Expand Down

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