trc: move free carat handling into parser - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
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---
(DIR) commit 7d6a248f2c68d70f58387afc69e73e695c3d940c
(DIR) parent 3caf5c238a886d06b438ec6d42f2609b8625463f
(HTM) Author: Russ Cox <rsc@swtch.com>
Date: Mon, 4 May 2020 23:20:08 -0400
rc: move free carat handling into parser
This fixes at least one shell script (printfont) that expected
'x'`{y}'z'
tto mean
'x'^`{y}^'z'
as it now does. Before it meant:
'x'^`{y} 'z'
One surprise is that adjacent lists get a free carat:
(x y z)(1 2 3)
is
(x1 y2 z3)
This doesn't affect any rc script in Plan 9 or plan9port.
Diffstat:
M man/man1/rc.1 | 26 +++-----------------------
M src/cmd/rc/lex.c | 6 +++---
M src/cmd/rc/parse.c | 158 +++++++++++++++++--------------
M src/cmd/rc/syn.y | 2 +-
M src/cmd/rc/test.rc | 11 +++++++++++
5 files changed, 106 insertions(+), 97 deletions(-)
---
(DIR) diff --git a/man/man1/rc.1 b/man/man1/rc.1
t@@ -290,28 +290,10 @@ then one operand must have one component, and the other must be non-empty,
and concatenation is distributive.
.PD
.SS Free Carets
-In most circumstances,
-.I rc
+.I Rc
will insert the
.B ^
operator automatically between words that are not separated by white space.
-Whenever one of
-.B $
-.B '
-.B `
-follows a quoted or unquoted word or an unquoted word follows a quoted word
-with no intervening blanks or tabs,
-a
-.B ^
-is inserted between the two.
-If an unquoted word immediately follows a
-.BR $
-and contains a character other than an alphanumeric, underscore,
-or
-.BR * ,
-a
-.B ^
-is inserted before the first such character.
Thus
.IP
.B cc -$flags $stem.c
t@@ -367,7 +349,7 @@ or
.I Fd1
is a previously opened file descriptor and
.I fd0
-becomes a new copy (in the sense of
+becomes a new copy (in the sense of
.IR dup (3))
of it.
A file descriptor may be closed by writing
t@@ -477,7 +459,7 @@ is executed.
The
.I command
is executed once for each
-.IR argument
+.IR argument
with that argument assigned to
.IR name .
If the argument list is omitted,
t@@ -982,8 +964,6 @@ changes
.PP
Functions that use here documents don't work.
.PP
-Free carets don't get inserted next to keywords.
-.PP
The
.BI <{ command }
syntax depends on the underlying operating system
(DIR) diff --git a/src/cmd/rc/lex.c b/src/cmd/rc/lex.c
t@@ -202,7 +202,7 @@ yylex(void)
* if the next character is the first character of a simple or compound word,
* we insert a `^' before it.
*/
- if(lastword){
+ if(lastword && flag['Y']){
lastword = 0;
if(d=='('){
advance();
t@@ -215,8 +215,8 @@ yylex(void)
}
}
inquote = 0;
- if(skipwhite() && flag['Z'])
- return SP;
+ if(skipwhite() && !flag['Y'])
+ return ' ';
switch(c = advance()){
case EOF:
lastdol = 0;
(DIR) diff --git a/src/cmd/rc/parse.c b/src/cmd/rc/parse.c
t@@ -23,7 +23,15 @@ static jmp_buf yyjmp;
static int
dropnl(int tok)
{
- while(tok == '\n')
+ while(tok == ' ' || tok == '\n')
+ tok = yylex();
+ return tok;
+}
+
+static int
+dropsp(int tok)
+{
+ while(tok == ' ')
tok = yylex();
return tok;
}
t@@ -49,7 +57,7 @@ parse(void)
// rc: { return 1;}
// | line '\n' {return !compile($1);}
- tok = yylex();
+ tok = dropsp(yylex());
if(tok == EOF)
return 1;
t = line(tok, &tok);
t@@ -117,6 +125,7 @@ brace(int tok)
// brace: '{' body '}' {$$=tree1(BRACE, $2);}
+ tok = dropsp(tok);
if(tok != '{')
syntax(tok);
t = body(yylex(), &tok);
t@@ -132,6 +141,7 @@ paren(int tok)
// paren: '(' body ')' {$$=tree1(PCMD, $2);}
+ tok = dropsp(tok);
if(tok != '(')
syntax(tok);
t = body(yylex(), &tok);
t@@ -172,11 +182,12 @@ yyredir(int tok, int *ptok)
syntax(tok);
case DUP:
r = yylval.tree;
- *ptok = yylex();
+ *ptok = dropsp(yylex());
break;
case REDIR:
r = yylval.tree;
- w = yyword(yylex(), ptok);
+ w = yyword(yylex(), &tok);
+ *ptok = dropsp(tok);
r = mung1(r, r->rtype==HERE?heredoc(w):w);
break;
}
t@@ -186,17 +197,67 @@ yyredir(int tok, int *ptok)
static tree*
cmd(int tok, int *ptok)
{
- tree *t1, *t2, *t3, *t4;
-
+ tok = dropsp(tok);
switch(tok) {
default:
return cmd2(tok, ptok);
+ }
+}
+
+static tree*
+cmd2(int tok, int *ptok)
+{
+ int op;
+ tree *t1, *t2;
+
+ // | cmd ANDAND cmd {$$=tree2(ANDAND, $1, $3);}
+ // | cmd OROR cmd {$$=tree2(OROR, $1, $3);}
+
+ t1 = cmd3(tok, &tok);
+ while(tok == ANDAND || tok == OROR) {
+ op = tok;
+ t2 = cmd3(dropnl(yylex()), &tok);
+ t1 = tree2(op, t1, t2);
+ }
+ *ptok = tok;
+ return t1;
+}
+
+static tree*
+cmd3(int tok, int *ptok)
+{
+ tree *t1, *t2, *t3;
+
+ // | cmd PIPE cmd {$$=mung2($2, $1, $3);}
+ t1 = cmd4(tok, &tok);
+ while(tok == PIPE) {
+ t2 = yylval.tree;
+ t3 = cmd4(dropnl(yylex()), &tok);
+ t1 = mung2(t2, t1, t3);
+ }
+ *ptok = tok;
+ return t1;
+}
+
+static tree*
+cmd4(int tok, int *ptok)
+{
+ tree *t1, *t2, *t3, *t4;
+
+ tok = dropsp(tok);
+ switch(tok) {
+ case ';':
+ case '&':
+ case '\n':
+ *ptok = tok;
+ return nil;
+
case IF:
// | IF paren {skipnl();} cmd {$$=mung2($1, $2, $4);}
// | IF NOT {skipnl();} cmd {$$=mung1($2, $4);}
t1 = yylval.tree;
- tok = yylex();
+ tok = dropsp(yylex());
if(tok == NOT) {
t1 = yylval.tree;
t2 = cmd(dropnl(yylex()), ptok);
t@@ -212,7 +273,7 @@ cmd(int tok, int *ptok)
// | FOR '(' word ')' {skipnl();} cmd
// {$$=mung3($1, $3, (tree *)0, $6);}
t1 = yylval.tree;
- tok = yylex();
+ tok = dropsp(yylex());
if(tok != '(')
syntax(tok);
t2 = yyword(yylex(), &tok);
t@@ -247,62 +308,8 @@ cmd(int tok, int *ptok)
t1 = yyword(yylex(), &tok);
tok = dropnl(tok); // doesn't work in yacc grammar but works here!
t2 = brace(tok);
- *ptok = yylex();
+ *ptok = dropsp(yylex());
return tree2(SWITCH, t1, t2);
- }
-}
-
-static tree*
-cmd2(int tok, int *ptok)
-{
- int op;
- tree *t1, *t2;
-
- // | cmd ANDAND cmd {$$=tree2(ANDAND, $1, $3);}
- // | cmd OROR cmd {$$=tree2(OROR, $1, $3);}
-
- t1 = cmd3(tok, &tok);
- while(tok == ANDAND || tok == OROR) {
- op = tok;
- t2 = cmd3(dropnl(yylex()), &tok);
- t1 = tree2(op, t1, t2);
- }
- *ptok = tok;
- return t1;
-}
-
-static tree*
-cmd3(int tok, int *ptok)
-{
- tree *t1, *t2, *t3;
-
- // | cmd PIPE cmd {$$=mung2($2, $1, $3);}
- t1 = cmd4(tok, &tok);
- while(tok == PIPE) {
- t2 = yylval.tree;
- t3 = cmd4(dropnl(yylex()), &tok);
- t1 = mung2(t2, t1, t3);
- }
- *ptok = tok;
- return t1;
-}
-
-static tree*
-cmd4(int tok, int *ptok)
-{
- tree *t1, *t2, *t3;
-
- switch(tok) {
- case ';':
- case '&':
- case '\n':
- *ptok = tok;
- return nil;
-
- case IF:
- case FOR:
- case SWITCH:
- case WHILE:
// Note: cmd: a && for(x) y && b is a && {for (x) {y && b}}.
return cmd(tok, ptok);
t@@ -315,7 +322,7 @@ cmd4(int tok, int *ptok)
return tree1(FN, t1);
}
t2 = brace(tok);
- *ptok = yylex();
+ *ptok = dropsp(yylex());
return tree2(FN, t1, t2);
case TWIDDLE:
t@@ -344,7 +351,7 @@ cmd4(int tok, int *ptok)
case '{':
// | brace epilog {$$=epimung($1, $2);}
t1 = brace(tok);
- tok = yylex();
+ tok = dropsp(yylex());
t2 = epilog(tok, ptok);
return epimung(t1, t2);
}
t@@ -396,6 +403,7 @@ words(int tok, int *ptok)
// | words word {$$=tree2(WORDS, $1, $2);}
t = nil;
+ tok = dropsp(tok);
while(iswordtok(tok))
t = tree2(WORDS, t, yyword(tok, &tok));
*ptok = tok;
t@@ -428,9 +436,19 @@ yyword(int tok, int *ptok)
// word1: keyword | comword
t = word1(tok, &tok);
- while(tok == '^')
- t = tree2('^', t, word1(yylex(), &tok));
- *ptok = tok;
+ for(;;) {
+ if(iswordtok(tok)) {
+ t = tree2('^', t, word1(tok, &tok));
+ continue;
+ }
+ tok = dropsp(tok);
+ if(tok == '^') {
+ t = tree2('^', t, word1(yylex(), &tok));
+ continue;
+ }
+ break;
+ }
+ *ptok = dropsp(tok);
return t;
}
t@@ -439,6 +457,7 @@ word1(int tok, int *ptok)
{
tree *w, *sub, *t;
+ tok = dropsp(tok);
switch(tok) {
default:
syntax(tok);
t@@ -458,7 +477,6 @@ word1(int tok, int *ptok)
// keyword: FOR|IN|WHILE|IF|NOT|TWIDDLE|BANG|SUBSHELL|SWITCH|FN
t = yylval.tree;
t->type = WORD;
- lastword = 1;
*ptok = yylex();
return t;
t@@ -466,7 +484,7 @@ word1(int tok, int *ptok)
// comword: '$' word1 {$$=tree1('$', $2);}
// | '$' word1 SUB words ')' {$$=tree2(SUB, $2, $4);}
w = word1(yylex(), &tok);
- if(tok == SUB) {
+ if(tok == '(') {
sub = words(yylex(), &tok);
if(tok != ')')
syntax(tok);
(DIR) diff --git a/src/cmd/rc/syn.y b/src/cmd/rc/syn.y
t@@ -1,4 +1,4 @@
-%term FOR IN WHILE IF NOT TWIDDLE BANG SUBSHELL SWITCH FN SP
+%term FOR IN WHILE IF NOT TWIDDLE BANG SUBSHELL SWITCH FN
%term WORD REDIR REDIRW DUP PIPE SUB
%term SIMPLE ARGLIST WORDS BRACE PAREN PCMD PIPEFD /* not used in syntax */
/* operator priorities -- lowest first */
(DIR) diff --git a/src/cmd/rc/test.rc b/src/cmd/rc/test.rc
t@@ -1,5 +1,9 @@
# test for parser
+a
+a b
+a|b
+a | b
{a; b; c}
x=y a && b || c
x=y a | b | c
t@@ -63,3 +67,10 @@ x ||
y
x |
y
+switch x {y} && z
+switch x {} | y
+
+OPTIONS=$OPTIONS' /axescount '^`{echo $1 | sed s/-a//}^' def'
+
+# bug in old printfont script - expected more free carats
+# OPTIONS=$OPTIONS' /axescount '`{echo $1 | sed s/-a//}' def'