6221832bc
Denys Vlasenko
2023-06-17
Subject
shell/math.h: update comments, rearrange struct members for smaller code
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shell/math.c+1 -1
| @@ -926,9 +926,9 @@ dbg(" numstack:%d val:%lld '%s'", (int)(numstackptr - numstack), numstackptr[ | |
| arith_t FAST_FUNC | |
| arith(arith_state_t *math_state, const char *expr) | |
| { | |
| + | math_state->evaluation_disabled = 0; |
| math_state->errmsg = NULL; | |
| math_state->list_of_recursed_names = NULL; | |
| - | math_state->evaluation_disabled = 0; |
| return evaluate_string(math_state, expr); | |
| } | |
shell/math.h+4 -22
| @@ -6,7 +6,6 @@ | |
| * | |
| * See math.c for internal documentation. | |
| */ | |
| - | |
| /* The math library has just one function: | |
| * | |
| * arith_t arith(arith_state_t *state, const char *expr); | |
| @@ -22,7 +21,6 @@ | |
| * "1 + 2 + 3" | |
| * you would obviously get back 6. | |
| */ | |
| - | |
| /* To add support to a shell, you need to implement three functions: | |
| * | |
| * lookupvar() - look up and return the value of a variable | |
| @@ -36,28 +34,12 @@ | |
| * setvar() - set a variable to some value | |
| * | |
| * If the arithmetic expansion does something like: | |
| - | * $(( i = 1)) |
| + | * $((i = 1)) |
| * then the math code will make a call like so: | |
| - | * setvar("i", "1", 0); |
| + | * setvar("i", "1"); |
| * The storage for the first two parameters are not allocated, so your | |
| * shell implementation will most likely need to strdup() them to save. | |
| - | * |
| - | * endofname() - return the end of a variable name from input |
| - | * |
| - | * The arithmetic code does not know about variable naming conventions. |
| - | * So when it is given an experession, it knows something is not numeric, |
| - | * but it is up to the shell to dictate what is a valid identifiers. |
| - | * So when it encounters something like: |
| - | * $(( some_var + 123 )) |
| - | * It will make a call like so: |
| - | * end = endofname("some_var + 123"); |
| - | * So the shell needs to scan the input string and return a pointer to the |
| - | * first non-identifier string. In this case, it should return the input |
| - | * pointer with an offset pointing to the first space. The typical |
| - | * implementation will return the offset of first char that does not match |
| - | * the regex (in C locale): ^[a-zA-Z_][a-zA-Z_0-9]* |
| */ | |
| - | |
| #ifndef SHELL_MATH_H | |
| #define SHELL_MATH_H 1 | |
| @@ -75,11 +57,11 @@ typedef const char* FAST_FUNC (*arith_var_lookup_t)(const char *name); | |
| typedef void FAST_FUNC (*arith_var_set_t)(const char *name, const char *val); | |
| typedef struct arith_state_t { | |
| + | uint64_t evaluation_disabled; |
| const char *errmsg; | |
| + | void *list_of_recursed_names; |
| arith_var_lookup_t lookupvar; | |
| arith_var_set_t setvar; | |
| - | uint64_t evaluation_disabled; |
| - | void *list_of_recursed_names; |
| } arith_state_t; | |
| arith_t FAST_FUNC arith(arith_state_t *state, const char *expr); | |