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dpgeorgedpgeorge
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Improve REPL compount statement detection.
1 parent 9d63932 commit 92c0656

5 files changed

Lines changed: 52 additions & 24 deletions

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‎py/lexer.c‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -10,6 +10,9 @@
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#define TAB_SIZE (8)
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13+
// TODO seems that CPython allows NULL byte in the input stream
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// don't know if that's intentional or not, but we don't allow it
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struct _py_lexer_t {
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const char *name; // name of source
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void *stream_data; // data for stream

‎py/repl.c‎

Lines changed: 44 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,44 @@
1+
#include "misc.h"
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#include "repl.h"
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4+
bool str_startswith_word(const char *str, const char *head) {
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int i;
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for (i = 0; str[i] && head[i]; i++) {
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if (str[i] != head[i]) {
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return false;
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}
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}
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return head[i] == '\0' && (str[i] == '\0' || !g_unichar_isalpha(str[i]));
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}
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14+
bool py_repl_is_compound_stmt(const char *line) {
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// compound if line starts with a certain keyword
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if (
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str_startswith_word(line, "if")
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|| str_startswith_word(line, "while")
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|| str_startswith_word(line, "for")
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|| str_startswith_word(line, "true")
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|| str_startswith_word(line, "with")
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|| str_startswith_word(line, "def")
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|| str_startswith_word(line, "class")
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|| str_startswith_word(line, "@")
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) {
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return true;
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}
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29+
// also "compound" if unmatched open bracket
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int n_paren = 0;
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int n_brack = 0;
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int n_brace = 0;
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for (const char *l = line; *l; l++) {
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switch (*l) {
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case '(': n_paren += 1; break;
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case ')': n_paren -= 1; break;
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case '[': n_brack += 1; break;
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case ']': n_brack -= 1; break;
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case '{': n_brace += 1; break;
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case '}': n_brace -= 1; break;
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}
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}
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return n_paren > 0 || n_brack > 0 || n_brace > 0;
44+
}

‎py/repl.h‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
1+
bool py_repl_is_compound_stmt(const char *line);

‎unix/Makefile‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -30,6 +30,7 @@ PY_O = \
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emitinlinethumb.o \
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runtime.o \
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vm.o \
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repl.o \
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OBJ = $(addprefix $(BUILD)/, $(SRC_C:.c=.o) $(PY_O))
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LIB = -lreadline

‎unix/main.c‎

Lines changed: 3 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -10,32 +10,10 @@
1010
#include "parse.h"
1111
#include "compile.h"
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#include "runtime.h"
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#include "repl.h"
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#include <readline/readline.h>
1516

16-
bool str_startswith_word(const char *str, const char *head) {
17-
int i;
18-
for (i = 0; str[i] && head[i]; i++) {
19-
if (str[i] != head[i]) {
20-
return false;
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}
22-
}
23-
return head[i] == '\0' && (str[i] == '\0' || !g_unichar_isalpha(str[i]));
24-
}
25-
26-
bool is_compound_stmt(const char *line) {
27-
// TODO also "compound" if unmatched open bracket
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return
29-
str_startswith_word(line, "if")
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|| str_startswith_word(line, "while")
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|| str_startswith_word(line, "for")
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|| str_startswith_word(line, "true")
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|| str_startswith_word(line, "with")
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|| str_startswith_word(line, "def")
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|| str_startswith_word(line, "class")
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|| str_startswith_word(line, "@");
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}
38-
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char *str_join(const char *s1, int sep_char, const char *s2) {
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int l1 = strlen(s1);
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int l2 = strlen(s2);
@@ -46,6 +24,7 @@ char *str_join(const char *s1, int sep_char, const char *s2) {
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l1 += 1;
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}
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memcpy(s + l1, s2, l2);
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s[l1 + l2] = 0;
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return s;
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}
5130

@@ -56,7 +35,7 @@ void do_repl() {
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// EOF
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return;
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}
59-
if (is_compound_stmt(line)) {
38+
if (py_repl_is_compound_stmt(line)) {
6039
for (;;) {
6140
char *line2 = readline("... ");
6241
if (line2 == NULL || strlen(line2) == 0) {

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