From 56eef91884524dfdfc4e2c227f323150996340dd Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pj@pehjota.net>
Date: Sat, 27 Feb 2016 18:29:41 -0500
Subject: eshtrans/frontend: Fix ungetc code and run_sublexer()

---
(limited to 'eshtrans')

diff --git a/eshtrans/frontend/lexer.esh b/eshtrans/frontend/lexer.esh
index 0b628a6..e0f703c 100644
--- a/eshtrans/frontend/lexer.esh
+++ b/eshtrans/frontend/lexer.esh
@@ -96,12 +96,21 @@ lgetc()
 	fi
 }
 
+lungetc()
+{
+	lbufi=$((${lbufi} - 2))
+	eval "c=\${lbufv_${lbufi}}"
+	lbufi=$((${lbufi} + 1))
+}
+
 lsetc()
 {
 	if [ ${lbufi} -ge ${lbufc} ]; then
 		c=''
 	else
+		lbufi=$((${lbufi} - 1))
 		eval "c=\${lbufv_${lbufi}}"
+		lbufi=$((${lbufi} + 1))
 	fi
 }
 
@@ -150,7 +159,8 @@ next()
 					continue
 					;;
 				esac
-				next_word \\
+				lungetc
+				next_word
 				return
 				;;
 			'#')
@@ -213,7 +223,8 @@ next()
 				return
 				;;
 			*)
-				next_word ''
+				lungetc
+				next_word
 				return
 				;;
 		esac
@@ -367,11 +378,9 @@ next_io()
 
 next_word()
 {
-	local prev_c="${1}"
-	shift 1
 	local res=
 
-	if ! res="$(scan_word false "${prev_c}")"; then
+	if ! res="$(scan_word false)"; then
 		exit 1
 	fi
 	ln_off=${res%%${RS}*}
@@ -406,8 +415,7 @@ next_word()
 scan_word()
 {
 	local in_param="${1}"
-	local prev_c="${2}"
-	shift 2
+	shift 1
 	local lines=
 	local word=
 	local quoted=
@@ -418,15 +426,6 @@ scan_word()
 	word=''
 	quoted=false
 
-	# Sort of a localized ungetc().
-	case "${prev_c}" in
-		'') ;;
-		*)
-			tmp_c="${c}"
-			c="${prev_c}"
-			;;
-	esac
-
 	while :; do
 		#dbg "parsing word char '$c' at lineno $lineno"
 		case "${c}" in
@@ -458,10 +457,7 @@ scan_word()
 					fi
 					;;
 				esac
-				case "${prev_c}" in
-					'') lgetc;;
-					*) c="${tmp_c}"; prev_c='';;
-				esac
+				lgetc
 				if ! res="$(scan_wordexp)"; then
 					exit 1
 				fi
@@ -488,10 +484,7 @@ scan_word()
 			\\)
 				#dbg 'first backslash in word'
 				word="${word}${c}"
-				case "${prev_c}" in
-					'') lgetc;;
-					*) c="${tmp_c}"; prev_c='';;
-				esac
+				lgetc
 				#dbg "next char: '$c'"
 				case "${c}" in '')
 					# Bash, ksh93, mksh, and zsh ignore a
@@ -510,17 +503,11 @@ scan_word()
 			\')
 				word="${word}${c}"
 				if ${quoted}; then
-					case "${prev_c}" in
-						'') lgetc;;
-						*) c="${tmp_c}"; prev_c='';;
-					esac
+					lgetc
 					continue
 				fi
 				while :; do
-					case "${prev_c}" in
-						'') lgetc;;
-						*) c="${tmp_c}"; prev_c='';;
-					esac
+					lgetc
 					word="${word}${c}"
 					case "${c}" in
 						'')
@@ -556,10 +543,7 @@ scan_word()
 				word="${word}${c}"
 				;;
 		esac
-		case "${prev_c}" in
-			'') lgetc;;
-			*) c="${tmp_c}"; prev_c='';;
-		esac
+		lgetc
 	done
 
 	if ${quoted}; then
@@ -592,7 +576,7 @@ scan_wordexp()
 					# Command substitution
 					if ! res="$(run_sublexer "sub${fname}" \
 							${lineno} "${start}" \
-							"${c}")"; then
+							${lbufi})"; then
 						exit 1
 					fi
 					lbufi="${res##*${RS}}"
@@ -859,7 +843,7 @@ run_sublexer()
 	local fn="${1}"
 	local ln="${2}"
 	local st="${3}"
-	local ch="${4}"
+	local i="${4}"
 	shift 4
 
 	# Initialize global variables.
@@ -870,7 +854,8 @@ run_sublexer()
 	here_awaiting_end=false
 	here_awaiting_word=false
 
-	c="${ch}"
+	lbufi="${i}"
+	lsetc
 	next
 
 	#dbg=true
--
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