How to trigger functions in subnodes in Ruby Treetop tree. (was:How to prevent ruby Treetop doing AST squashing)
Question
I am been using treetop for a while. I wrote rules following
http://thingsaaronmade.com/blog/a-quick-intro-to-writing-a-parser-using-treetop.html
I can parse my whole input string but i none of the other to_array function gets triggered other than the initial one.
Then I found https://whitequark.org/blog/2011/09/08/treetop-typical-errors/ which talk about AST squashing and I figured out that my rule is doing the same.
The first rule I have is
rule bodies
blankLine* interesting:(body+) blankLine* <Bodies>
end
and everything is getting gobbled up by body .
Can someone suggest me what can I do to fix this?
Edit Adding code snippet:
grammar Sexp
rule bodies
blankLine* interesting:(body+) blankLine* <Bodies>
end
rule body
commentPortString (ifdef_blocks / interface)+ (blankLine / end_of_file) <Body>
end
rule interface
space? (intf / intfWithSize) space? newLine <Interface>
end
rule commentPortString
space? '//' space portString space? <CommentPortString>
end
rule portString
'Port' space? '.' newLine <PortString>
end
rule expression
space? '(' body ')' space? <Expression>
end
rule intf
(input / output) space wire:wireName space? ';' <Intf>
end
rule intfWithSize
(input / output) space? width:ifWidth space? wire:wireName space? ';' <IntfWithSize>
end
rule input
'input' <InputDir>
end
rule output
'output' <OutputDir>
end
rule ifdef_blocks
ifdef_line (interface / ifdef_block)* endif_line <IfdefBlocks>
end
rule ifdef_block
ifdef_line interface* endif_line <IfdefBlocks>
end
rule ifdef_line
space? (ifdef / ifndef) space+ allCaps space? newLine <IfdefLine>
end
rule endif_line
space? (endif) space? newLine <EndifLine>
end
rule ifdef
'`ifdef' <Ifdef>
end
rule ifndef
'`ifndef' <Ifndef>
end
rule endif
'`endif' <Endif>
end
rule ifWidth
'[' space? msb:digits space? ':' space? lsb:digits ']' <IfWidth>
end
rule digits
[0-9]+ <Digits>
end
rule integer
('+' / '-')? [0-9]+ <IntegerLiteral>
end
rule float
('+' / '-')? [0-9]+ (('.' [0-9]+) / ('e' [0-9]+)) <FloatLiteral>
end
rule string
'"' ('\"' / !'"' .)* '"' <StringLiteral>
end
rule identifier
[a-zA-Z\=\*] [a-zA-Z0-9_\=\*]* <Identifier>
end
rule allCaps
[A-Z] [A-Z0-9_]*
end
rule wireName
[a-zA-Z] [a-zA-Z0-9_]* <WireName>
end
rule non_space
!space .
end
rule space
[^\S\n]+
end
rule non_space
!space .
end
rule blankLine
space* newLine
end
rule not_newLine
!newLine .
end
rule newLine
[\n\r]
end
rule end_of_file
!.
end
end
Test string
// Port.
input CLK;
// Port.
input REFCLK;
// Port.
input [ 41:0] mem_power_ctrl;
output data;
EDIT: Adding more details
The test code is checked into: https://github.com/justrajdeep/treetop_ruby_issue .
As you would see in my node_extensions.rb all the nodes except the Bodies raise an exception in the method to_array . But none of the exceptions trigger.
2 answers
solution1
1 ACCPTED 2018-08-02 21:16:05
You call to_array on tree , which is a Bodies . That is the only thing you ever call to_array on, so no other to_array method will be called.
If you want to_array to be called on child nodes of the Bodies node, Bodies#to_array needs to call to_array on those child nodes. So if you want to call it on the Body nodes you labelled interesting , you should iterate over interesting and call .to_array on each element.
solution2
0 2018-08-02 18:09:16
Try breaking (body+) into a new rule like this:
rule bodies
blankLine* interesting:interesting blankLine* <Bodies>
end
rule interesting
body+ <Interesting>
end
Otherwise, it would be helpful to see the SyntaxNode classes.
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