diff options
| -rw-r--r-- | parsing/lexer.sh | 66 | ||||
| -rw-r--r-- | parsing/parse.sh | 45 |
2 files changed, 48 insertions, 63 deletions
diff --git a/parsing/lexer.sh b/parsing/lexer.sh index 928021e..a3ab762 100644 --- a/parsing/lexer.sh +++ b/parsing/lexer.sh @@ -1,5 +1,6 @@ fname= lineno= +start= c= tok= tokens= @@ -399,9 +400,9 @@ scan_wordexp() ;; *) # Command substitution - if ! res="$(parse_sub "${fname}" \ - ${lineno} "${c}" false)" - then + if ! res="$(run_sublexer "sub${fname}" \ + ${lineno} "${start}" \ + "${c}")"; then exit 1 fi ln_off=${res%%${RS}*} @@ -411,7 +412,7 @@ scan_wordexp() toks="${res%%${RS}*}" lineno=${ln_off} wordexp="\$(${STX}${toks}${ETX})" - # ")" is recognized in parse_sub(). + # ")" is recognized in run_sublexer(). ;; esac ;; @@ -608,42 +609,63 @@ error() exit 1 } -init_lexer() +run_sublexer() { local fn="${1}" local ln="${2}" - local char="${3}" - shift 3 + local st="${3}" + local ch="${4}" + shift 4 + # Initialize global variables. fname="${fn}" lineno=${ln} + start="${st}" tokens='' - case "${char}" in - '') - pgetc + + c="${ch}" + next + + #dbg=true + # If this returns (does not exit), there are no errors. + ${start} + case "${tok%${US}*}" in + T_RPAREN) ;; *) - c="${char}" + synerr 'Missing ")"' ;; esac - next -} -get_lineno() -{ - printf '%d' ${lineno} + printf "%d${RS}%c${RS}%s" ${lineno} "${c}" "${tokens}" return 0 } -get_lexer_char() +run_lexer() { - printf '%c' "${c}" - return 0 -} + local fn="${1}" + local st="${2}" + shift 2 -get_tokens() -{ + # Initialize global variables. + fname="${fn}" + lineno=1 + start="${st}" + tokens='' + + # Read the first character and recognize the first token. + pgetc + next + + # If this returns (does not exit), there are no errors. + ${start} + if ! accept T_EOF; then + synexp '' + fi + + # Return the tokens. printf '%s' "${tokens}" + return 0 } diff --git a/parsing/parse.sh b/parsing/parse.sh index d9fb6a1..196ad84 100644 --- a/parsing/parse.sh +++ b/parsing/parse.sh @@ -5,10 +5,11 @@ ETX="$(printf '\003.')"; ETX="${ETX%.}" RS="$(printf '\036.')"; RS="${RS%.}" US="$(printf '\037.')"; US="${US%.}" +dbg=true +dbg=false + dbg() { - dbg=true - dbg=false if ${dbg}; then printf 'DEBUG: %s\n' "${@}" >&2 fi @@ -583,50 +584,12 @@ sequential_sep() return 1 } -# Maybe parse() should just tell the lexer what the starting production (parser -# entry point) is. -parse_sub() -{ - local fn="${1}" - local ln="${2}" - local lexer_char="${3}" - local complete="${4}" - shift 3 - - init_lexer "${fn}" ${ln} "${lexer_char}" - - # If this returns (does not exit), there are no errors. - complete_command - if ${complete} && ! accept T_EOF; then - synexp '' - fi - if ! ${complete}; then - case "${tok%${US}*}" in - T_RPAREN) - ;; - *) - synerr 'Missing ")"' - ;; - esac - fi - - get_lineno - printf '%c' "${RS}" - get_lexer_char - printf '%c' "${RS}" - get_tokens - - return 0 -} - parse() { local fn="${1}" shift 1 - local toks= - if toks="$(parse_sub "${fn}" 1 '' true)"; then - printf '%s\n' "${toks#*${RS}*${RS}}" + if run_lexer "${fn}" complete_command; then return 0 fi return 1 |