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almost done # and ##

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pommicket 2022-01-09 18:39:16 -05:00
parent 141bc9e49a
commit a2e594c9be
2 changed files with 61 additions and 5 deletions
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8
05/main.c
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@ -1,8 +1,12 @@
#define STRINGIFY2(x) #x
#define STRINGIFY2(x) # x
#define STRINGIFY(x) STRINGIFY2(x)
#define JOIN2(x,y) x ## y
#define JOIN(x,y) JOIN2(x, y)
#define X 22
STRINGIFY(X)
JOIN2(X, X)
STRINGIFY(X)
#define E 5
#define D E

58
05/preprocess.b
View file

@ -1,10 +1,13 @@
; returns a string of null character-separated preprocessing tokens
; returns a string of null character-separated preprocessing tokens and space characters
; this corresponds to translation phases 1-3 in the C89 standard
; each sequence of two or more spaces is replaced with a single space
; spaces following # and around ## are removed
function split_into_preprocessing_tokens
argument filename
local fd
local file_contents
local pptokens
local pptokens2
local p
local b
local c
@ -316,7 +319,54 @@ function split_into_preprocessing_tokens
goto pptokens_loop
:pptokens_loop_end
free(file_contents)
pptokens2 = file_contents ; repurpose file contents
; replace each sequence of two or more spaces with a single space
; "Whether each nonempty sequence of other white-space characters is
; retained or replaced by one space character is implementation-defined." (C89 § 2.1.1.2)
in = pptokens
out = pptokens2
:join_spaces_loop
if *1in == 0 goto join_spaces_loop_end
c = *1in
pptoken_copy_and_advance(&in, &out)
if c == 32 goto join_spaces
goto join_spaces_loop
:join_spaces
pptoken_skip_spaces(&in)
goto join_spaces_loop
:join_spaces_loop_end
*1out = 0
; delete space surrounding ## and following #
in = pptokens2
out = pptokens
:delete_hash_spaces_loop
c = *1in
if c == 0 goto delete_hash_spaces_loop_end
pptoken_copy_and_advance(&in, &out)
if c == '# goto delete_hash_spaces_hash
:delete_hash_spaces_hash
p = in + 1
if *1p == '# goto delete_surrounding_space
:delete_hash_spaces_skip_spaces
pptoken_skip_spaces(&in)
goto delete_hash_spaces_loop
:delete_surrounding_space
p = out - 2 ; ## can't appear at start of file
if *1p != 32 goto delete_hash_spaces_skip_spaces ; no space before ##
; space before ##
; remove it
out -= 2
*1out = 0
goto delete_hash_spaces_skip_spaces
:delete_hash_spaces_loop_end
*1out = 0
free(pptokens2)
close(fd)
return pptokens
@ -444,7 +494,7 @@ function translation_phase_4
goto phase4_line
:phase4_try_replacements
macro_replacement(filename, line_number, &in, &out)
goto phase4_line
goto process_pptoken
:pp_directive
pptoken_skip(&in) ; skip #
pptoken_skip_spaces(&in)
@ -454,6 +504,8 @@ function translation_phase_4
if b != 0 goto pp_directive_error
b = str_equals(in, .str_define)
if b != 0 goto pp_directive_define
puts(in)
putc(10)
goto unrecognized_directive
:pp_directive_error
fputs(2, filename)