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-rw-r--r--bin/sh/TOUR37
1 files changed, 8 insertions, 29 deletions
diff --git a/bin/sh/TOUR b/bin/sh/TOUR
index 8448966..4b61bdf 100644
--- a/bin/sh/TOUR
+++ b/bin/sh/TOUR
@@ -27,10 +27,8 @@ programs is:
mkbuiltins builtins builtins.h builtins.c
mkinit *.c init.c
mknodes nodetypes nodes.h nodes.c
- mksignames - signames.h signames.c
mksyntax - syntax.h syntax.c
mktokens - token.h
- bltin/mkexpr unary_op binary_op operators.h operators.c
There are undoubtedly too many of these. Mkinit searches all the
C source files for entries looking like:
@@ -64,14 +62,6 @@ tion:
Preprocessor #define statements are copied to init.c without any
special action to request this.
-INDENTATION: The ash source is indented in multiples of six
-spaces. The only study that I have heard of on the subject con-
-cluded that the optimal amount to indent is in the range of four
-to six spaces. I use six spaces since it is not too big a jump
-from the widely used eight spaces. If you really hate six space
-indentation, use the adjind (source included) program to change
-it to something else.
-
EXCEPTIONS: Code for dealing with exceptions appears in
exceptions.c. The C language doesn't include exception handling,
so I implement it using setjmp and longjmp. The global variable
@@ -115,7 +105,7 @@ repeatedly parses and executes commands.
OPTIONS.C: This file contains the option processing code. It is
called from main to parse the shell arguments when the shell is
-invoked, and it also contains the set builtin. The -i and -j op-
+invoked, and it also contains the set builtin. The -i and -m op-
tions (the latter turns on job control) require changes in signal
handling. The routines setjobctl (in jobs.c) and setinteractive
(in trap.c) are called to handle changes to these options.
@@ -123,10 +113,11 @@ handling. The routines setjobctl (in jobs.c) and setinteractive
PARSING: The parser code is all in parser.c. A recursive des-
cent parser is used. Syntax tables (generated by mksyntax) are
used to classify characters during lexical analysis. There are
-three tables: one for normal use, one for use when inside single
-quotes, and one for use when inside double quotes. The tables
-are machine dependent because they are indexed by character vari-
-ables and the range of a char varies from machine to machine.
+four tables: one for normal use, one for use when inside single
+quotes and dollar single quotes, one for use when inside double
+quotes and one for use in arithmetic. The tables are machine
+dependent because they are indexed by character variables and
+the range of a char varies from machine to machine.
PARSE OUTPUT: The output of the parser consists of a tree of
nodes. The various types of nodes are defined in the file node-
@@ -242,12 +233,7 @@ The routine shellexec is the interface to the exec system call.
EXPAND.C: Arguments are processed in three passes. The first
(performed by the routine argstr) performs variable and command
substitution. The second (ifsbreakup) performs word splitting
-and the third (expandmeta) performs file name generation. If the
-"/u" directory is simulated, then when "/u/username" is replaced
-by the user's home directory, the flag "didudir" is set. This
-tells the cd command that it should print out the directory name,
-just as it would if the "/u" directory were implemented using
-symbolic links.
+and the third (expandmeta) performs file name generation.
VAR.C: Variables are stored in a hash table. Probably we should
switch to extensible hashing. The variable name is stored in the
@@ -292,14 +278,7 @@ when the program is linked into ash. This #define should appear
before bltin.h is included; bltin.h will #undef main if the pro-
gram is to be compiled stand-alone.
-CD.C: This file defines the cd and pwd builtins. The pwd com-
-mand runs /bin/pwd the first time it is invoked (unless the user
-has already done a cd to an absolute pathname), but then
-remembers the current directory and updates it when the cd com-
-mand is run, so subsequent pwd commands run very fast. The main
-complication in the cd command is in the docd command, which
-resolves symbolic links into actual names and informs the user
-where the user ended up if he crossed a symbolic link.
+CD.C: This file defines the cd and pwd builtins.
SIGNALS: Trap.c implements the trap command. The routine set-
signal figures out what action should be taken when a signal is
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