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include "lexoper.h"
define start_ 90
# LEXER -- Lexically analyze a rule base
#
# B.Simon 25-Apr-88 Original
procedure lexer (rb, oper, value, maxch)
pointer rb # i: Pointer to descriptor of rule base
int oper # o: Operator type found
char value[ARB] # o: Text of operator
int maxch # i: Maximum length of string
#--
char dic_text[2]
int junk, old_index, dic_index, dic_oper[5]
pointer sp, ch, blanks
data dic_oper /SEPOPR, IMPOPR, OROPR, ANDOPR, EQOPR/
string dict "/;/=>/||/&&/=/"
bool streq()
int getline(), ctowrd(), span(), nospan(), strdic()
begin
# Allocate an array to hold whitespace
call smark (sp)
call salloc (blanks, SZ_LINE, TY_CHAR)
# Skip over leading whitespace
start_ junk = span (" \t", RB_LINE(rb), RB_INDEX(rb), Memc[blanks], SZ_LINE)
# Branch on first non-white character
ch = RB_CHARPTR(rb)
# End of line or beginning of comment
if (Memc[ch] == '\n' || Memc[ch] == '#' || Memc[ch] == EOS) {
if (getline (RB_FILE(rb), RB_LINE(rb)) == EOF) {
oper = ENDOPR
value[1] = EOS
} else {
RB_NLINE(rb) = RB_NLINE(rb) + 1
RB_INDEX(rb) = 1
goto start_
}
# Quoted identifier
} else if (Memc[ch] == '\'' || Memc[ch] == '"') {
junk = ctowrd (RB_LINE(rb), RB_INDEX(rb), value, maxch)
oper = IDOPR
# Unquoted identifier
} else if (nospan ("=&|; \t\n", RB_LINE(rb), RB_INDEX(rb),
value, maxch) > 0 ) {
oper = IDOPR
# Other operator
} else {
old_index = RB_INDEX(rb)
junk = span ("=>&|;", RB_LINE(rb), RB_INDEX(rb), value, 2)
dic_index = strdic (value, dic_text, 2, dict)
if (dic_index > 0 && streq (value, dic_text)) {
oper = dic_oper[dic_index]
} else {
RB_INDEX(rb) = old_index
junk = ctowrd (RB_LINE(rb), RB_INDEX(rb), value, maxch)
oper = IDOPR
}
}
call sfree (sp)
end
# LEXINIT -- Initialize the lexical analyzer
procedure lexinit (rbase, rb)
char rbase[ARB] # i: Name of rule base file
pointer rb # o: Pointer to rule base descriptor
#--
int open()
errchk calloc, open
begin
call malloc (rb, RB_LENGTH, TY_INT)
RB_FILE(rb) = open (rbase, READ_ONLY, TEXT_FILE)
RB_INDEX(rb) = 1
RB_NLINE(rb) = 0
RB_LINE(rb) = EOS
end
#LEXCLOSE -- Close the lexical analyzer
procedure lexclose (rb)
pointer rb # i: Pointer to rule base descriptor
#--
errchk close, mfree
begin
call close (RB_FILE(rb))
call mfree (rb, TY_INT)
end
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