blob: 6c77eb6ed9f76b319088789fa420a67eeaaa2e93 (
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|
sc=
sgetc()
{
sc="$(dd bs=1 count=1 2>/dev/null; printf '.')"
sc="${sc%.}"
}
toktext()
{
local t="${1}"
shift 1
local n=
case "${t%${US}*}" in
# Operators
T_EOF) n='';;
T_NEWLINE) n="${LF}";;
T_AND) n='&';;
T_SEMI) n=';';;
T_AND_IF) n='&&';;
T_OR_IF) n='||';;
T_DSEMI) n=';;';;
T_LESS) n='<';;
T_GREAT) n='>';;
T_DLESS) n='<<';;
T_DGREAT) n='>>';;
T_LESS) n='<';;
T_LESSAND) n='<&';;
T_GREAT) n='>';;
T_GREATAND) n='>&';;
T_LESSGREAT) n='<>';;
T_DLESSDASH) n='<<-';;
T_CLOBBER) n='>|';;
T_PIPE) n='|';;
T_LPAREN) n='(';;
T_RPAREN) n=')';;
# Reserved words
T_IF) n='if';;
T_THEN) n='then';;
T_ELSE) n='else';;
T_ELIF) n='elif';;
T_FI) n='fi';;
T_DO) n='do';;
T_DONE) n='done';;
T_CASE) n='case';;
T_ESAC) n='esac';;
T_WHILE) n='while';;
T_UNTIL) n='until';;
T_FOR) n='for';;
T_LBRACE) n='{';;
T_RBRACE) n='}';;
T_BANG) n='!';;
T_IN) n='in';;
# Special symbols
T_NAME) n="${t#*${US}}";;
T_FNAME) n="${t#*${US}}";;
T_CMDNAME) n="${t#*${US}}";;
T_IO_NUMBER) n="${t#*${US}}";;
T_WORD) n="${t#*${US}}";;
T_ASSIGNMENT_WORD) n="${t#*${US}}";;
# Unknown
*) n='';;
esac
printf '%s' "${n}"
}
codegen_sub()
{
local array="${1}"
shift 1
IFS="${RS}"
for t in ${array}; do
toktext "${t}"
case "${t%${US}*}" in
T_NEWLINE)
;;
*)
printf ' '
;;
esac
done
unset IFS
}
# The token stack is encoded in a string in the following grammar:
# Terminal symbols:
# TOKEN
# Production rules:
# stack = tokens [ '<SOH>' type '<STX>' stack '<ETX>' [ tokens ] ] ;
# tokens = TOKEN { '<RS>' TOKEN } ;
# type = 'C' ;
# We need to recurse through this stack to get to all the tokens.
# Each element in the stack (an array of tokens) gets run through the codegen to
# become text that is inserted into the array below.
parse_stack()
{
local array=
array=''
while :; do
sgetc
case "${sc}" in
'')
# EOF
break
;;
"${SOH}")
# New stack element
sgetc
case "${sc}" in
'C')
# Command substitution
sgetc # STX
array="${array}$(parse_stack)."
array="${array%.}"
;;
esac
;;
"${ETX}")
# End of stack element
break
;;
*)
# Token character
array="${array}${sc}"
;;
esac
done
codegen_sub "${array}"
}
codegen()
{
local toks="${1}"
shift 1
if printf '%s' "${toks}" | parse_stack; then
return 0
else
return 1
fi
}
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