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https://github.com/fish-shell/fish-shell
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Switch to direct evaluation
Both constant values and functions are represented as `te_fun_t`. This struct defines `operator()` which evaluates the function with the given arguments.
This commit is contained in:
Juho Eerola
parent
73bc453eaf
commit
074537a8ac
1 changed files with 237 additions and 369 deletions
606
src/tinyexpr.cpp
606
src/tinyexpr.cpp
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@ -27,29 +27,68 @@
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#include <ctype.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <algorithm>
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#include <cmath>
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#include <cstring>
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#include <iterator>
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#include <utility>
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#include <vector>
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#include "common.h"
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#include "fallback.h" // IWYU pragma: keep
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#include "wutil.h"
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// TODO: It would be nice not to rely on a typedef for this, especially one that can only do
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// functions with two args.
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using te_fun2 = double (*)(double, double);
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using te_fun1 = double (*)(double);
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using te_fun0 = double (*)();
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struct te_fun_t {
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using fn_2 = double (*)(double, double);
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using fn_1 = double (*)(double);
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using fn_0 = double (*)();
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enum {
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TE_CONSTANT = 0,
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TE_FUNCTION0,
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TE_FUNCTION1,
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TE_FUNCTION2,
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te_fun_t(double val) : type_{CONSTANT}, arity_{0}, value{val} {}
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te_fun_t(fn_0 fn) : type_{FUNCTION}, arity_{0}, fun0{fn} {}
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te_fun_t(fn_1 fn) : type_{FUNCTION}, arity_{1}, fun1{fn} {}
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te_fun_t(fn_2 fn) : type_{FUNCTION}, arity_{2}, fun2{fn} {}
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bool operator==(fn_2 fn) const { return arity_ == 2 && fun2 == fn; }
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[[nodiscard]] int arity() const { return arity_; }
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double operator()() const {
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assert(arity_ == 0);
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return type_ == CONSTANT ? value : fun0();
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}
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double operator()(double a, double b) const {
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assert(arity_ == 2);
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return fun2(a, b);
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}
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double operator()(const std::vector<double> &args) const {
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if (arity_ != static_cast<int>(args.size())) return NAN;
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switch (arity_) {
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case 0:
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return type_ == CONSTANT ? value : fun0();
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case 1:
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return fun1(args[0]);
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case 2:
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return fun2(args[0], args[1]);
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}
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return NAN;
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}
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private:
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enum {
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CONSTANT,
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FUNCTION,
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} type_;
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int arity_;
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union {
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double value;
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fn_0 fun0;
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fn_1 fun1;
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fn_2 fun2;
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};
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};
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enum te_state_type_t {
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TOK_NULL,
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TOK_ERROR,
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TOK_END,
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@ -57,96 +96,42 @@ enum {
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TOK_OPEN,
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TOK_CLOSE,
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TOK_NUMBER,
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TOK_FUNCTION,
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TOK_INFIX
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};
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static int get_arity(const int type) {
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if (type == TE_FUNCTION2) return 2;
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if (type == TE_FUNCTION1) return 1;
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return 0;
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}
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struct te_expr_t {
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int type;
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union {
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double value;
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te_fun0 fun0;
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te_fun1 fun1;
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te_fun2 fun2;
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};
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te_expr_t *parameters[];
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};
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struct te_builtin {
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const wchar_t *name;
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void *address;
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int type;
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};
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struct state {
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explicit state(const wchar_t *expr) : start{expr}, next{expr} { next_token(); }
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te_expr_t *expr();
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explicit state(const wchar_t *expr) : start_{expr}, next_{expr} { next_token(); }
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double eval() { return expr(); }
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union {
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double value;
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void *function;
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};
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const wchar_t *start;
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const wchar_t *next;
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int type;
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te_error_type_t error{TE_ERROR_NONE};
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[[nodiscard]] te_error_t error() const {
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if (type_ == TOK_END) return {TE_ERROR_NONE, 0};
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te_error_t err{error_, static_cast<int>(next_ - start_) + 1};
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if (error_ == TE_ERROR_NONE) {
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// If we're not at the end but there's no error, then that means we have a
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// superfluous token that we have no idea what to do with.
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err.type = TE_ERROR_TOO_MANY_ARGS;
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}
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return err;
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}
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private:
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te_state_type_t type_{TOK_NULL};
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te_error_type_t error_{TE_ERROR_NONE};
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const wchar_t *start_;
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const wchar_t *next_;
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te_fun_t current_{NAN};
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void next_token();
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te_expr_t *power();
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te_expr_t *base();
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te_expr_t *factor();
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te_expr_t *term();
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double expr();
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double power();
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double base();
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double factor();
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double term();
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};
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// TODO: That move there? Ouch. Replace with a proper class with a constructor.
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#define NEW_EXPR(type, ...) new_expr((type), std::move((const te_expr_t *[]){__VA_ARGS__}))
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static te_expr_t *new_expr(const int type, const te_expr_t *parameters[]) {
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const int arity = get_arity(type);
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const int psize = sizeof(te_expr_t *) * arity;
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const int size = sizeof(te_expr_t) + psize;
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auto ret = static_cast<te_expr_t *>(malloc(size));
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// This sets float to 0, which depends on the implementation.
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// We rely on IEEE-754 floats anyway, so it's okay.
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std::memset(ret, 0, size);
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if (arity && parameters) {
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std::memcpy(ret->parameters, parameters, psize);
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}
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ret->type = type;
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return ret;
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}
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/* Frees the expression. */
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/* This is safe to call on NULL pointers. */
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static void te_free(te_expr_t *n);
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static void te_free_parameters(te_expr_t *n) {
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if (!n) return;
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int arity = get_arity(n->type);
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// Free all parameters from the back to the front.
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while (arity > 0) {
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te_free(n->parameters[arity - 1]);
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arity--;
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}
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}
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static void te_free(te_expr_t *n) {
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if (!n) return;
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te_free_parameters(n);
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free(n);
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}
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static constexpr double pi() { return M_PI; }
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static constexpr double tau() { return 2 * M_PI; }
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static constexpr double e() { return M_E; }
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static double fac(double a) { /* simplest version of fac */
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if (a < 0.0) return NAN;
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if (a > UINT_MAX) return INFINITY;
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@ -203,40 +188,47 @@ static double min(double a, double b) {
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return a < b ? a : b;
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}
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struct te_builtin {
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const wchar_t *name;
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te_fun_t fn;
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};
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static const te_builtin functions[] = {
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/* must be in alphabetical order */
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{L"abs", reinterpret_cast<void *>(static_cast<te_fun1>(std::fabs)), TE_FUNCTION1},
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{L"acos", reinterpret_cast<void *>(static_cast<te_fun1>(std::acos)), TE_FUNCTION1},
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{L"asin", reinterpret_cast<void *>(static_cast<te_fun1>(std::asin)), TE_FUNCTION1},
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{L"atan", reinterpret_cast<void *>(static_cast<te_fun1>(std::atan)), TE_FUNCTION1},
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{L"atan2", reinterpret_cast<void *>(static_cast<te_fun2>(std::atan2)), TE_FUNCTION2},
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{L"bitand", reinterpret_cast<void *>(static_cast<te_fun2>(bit_and)), TE_FUNCTION2},
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{L"bitor", reinterpret_cast<void *>(static_cast<te_fun2>(bit_or)), TE_FUNCTION2},
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{L"bitxor", reinterpret_cast<void *>(static_cast<te_fun2>(bit_xor)), TE_FUNCTION2},
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{L"ceil", reinterpret_cast<void *>(static_cast<te_fun1>(std::ceil)), TE_FUNCTION1},
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{L"cos", reinterpret_cast<void *>(static_cast<te_fun1>(std::cos)), TE_FUNCTION1},
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{L"cosh", reinterpret_cast<void *>(static_cast<te_fun1>(std::cosh)), TE_FUNCTION1},
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{L"e", reinterpret_cast<void *>(static_cast<te_fun0>(e)), TE_FUNCTION0},
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{L"exp", reinterpret_cast<void *>(static_cast<te_fun1>(std::exp)), TE_FUNCTION1},
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{L"fac", reinterpret_cast<void *>(static_cast<te_fun1>(fac)), TE_FUNCTION1},
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{L"floor", reinterpret_cast<void *>(static_cast<te_fun1>(std::floor)), TE_FUNCTION1},
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{L"ln", reinterpret_cast<void *>(static_cast<te_fun1>(std::log)), TE_FUNCTION1},
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{L"log", reinterpret_cast<void *>(static_cast<te_fun1>(std::log10)), TE_FUNCTION1},
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{L"log10", reinterpret_cast<void *>(static_cast<te_fun1>(std::log10)), TE_FUNCTION1},
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{L"log2", reinterpret_cast<void *>(static_cast<te_fun1>(std::log2)), TE_FUNCTION1},
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{L"max", reinterpret_cast<void *>(static_cast<te_fun2>(max)), TE_FUNCTION2},
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{L"min", reinterpret_cast<void *>(static_cast<te_fun2>(min)), TE_FUNCTION2},
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{L"ncr", reinterpret_cast<void *>(static_cast<te_fun2>(ncr)), TE_FUNCTION2},
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{L"npr", reinterpret_cast<void *>(static_cast<te_fun2>(npr)), TE_FUNCTION2},
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{L"pi", reinterpret_cast<void *>(static_cast<te_fun0>(pi)), TE_FUNCTION0},
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{L"pow", reinterpret_cast<void *>(static_cast<te_fun2>(std::pow)), TE_FUNCTION2},
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{L"round", reinterpret_cast<void *>(static_cast<te_fun1>(std::round)), TE_FUNCTION1},
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{L"sin", reinterpret_cast<void *>(static_cast<te_fun1>(std::sin)), TE_FUNCTION1},
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{L"sinh", reinterpret_cast<void *>(static_cast<te_fun1>(std::sinh)), TE_FUNCTION1},
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{L"sqrt", reinterpret_cast<void *>(static_cast<te_fun1>(std::sqrt)), TE_FUNCTION1},
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{L"tan", reinterpret_cast<void *>(static_cast<te_fun1>(std::tan)), TE_FUNCTION1},
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{L"tanh", reinterpret_cast<void *>(static_cast<te_fun1>(std::tanh)), TE_FUNCTION1},
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{L"tau", reinterpret_cast<void *>(static_cast<te_fun0>(tau)), TE_FUNCTION0},
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// clang-format off
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{L"abs", std::fabs},
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{L"acos", std::acos},
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{L"asin", std::asin},
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{L"atan", std::atan},
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{L"atan2", std::atan2},
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{L"bitand", bit_and},
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{L"bitor", bit_or},
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{L"bitxor", bit_xor},
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{L"ceil", std::ceil},
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{L"cos", std::cos},
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{L"cosh", std::cosh},
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{L"e", M_E},
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{L"exp", std::exp},
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{L"fac", fac},
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{L"floor", std::floor},
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{L"ln", std::log},
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{L"log", std::log10},
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{L"log10", std::log10},
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{L"log2", std::log2},
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{L"max", max},
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{L"min", min},
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{L"ncr", ncr},
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{L"npr", npr},
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{L"pi", M_PI},
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{L"pow", std::pow},
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{L"round", std::round},
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{L"sin", std::sin},
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{L"sinh", std::sinh},
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{L"sqrt", std::sqrt},
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{L"tan", std::tan},
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{L"tanh", std::tanh},
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{L"tau", 2 * M_PI},
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// clang-format on
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};
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static const te_builtin *find_builtin(const wchar_t *name, int len) {
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@ -263,86 +255,76 @@ static constexpr double divide(double a, double b) {
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return b ? a / b : a ? copysign(1, a) * copysign(1, b) * INFINITY : NAN;
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}
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static constexpr double negate(double a) { return -a; }
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void state::next_token() {
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type = TOK_NULL;
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type_ = TOK_NULL;
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do {
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if (!*next) {
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type = TOK_END;
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if (!*next_) {
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type_ = TOK_END;
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return;
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}
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/* Try reading a number. */
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if ((next[0] >= '0' && next[0] <= '9') || next[0] == '.') {
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value = fish_wcstod(next, const_cast<wchar_t **>(&next));
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type = TOK_NUMBER;
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if ((next_[0] >= '0' && next_[0] <= '9') || next_[0] == '.') {
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current_ = fish_wcstod(next_, const_cast<wchar_t **>(&next_));
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type_ = TOK_NUMBER;
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} else {
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/* Look for a function call. */
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// But not when it's an "x" followed by whitespace
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// - that's the alternative multiplication operator.
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if (next[0] >= 'a' && next[0] <= 'z' && !(next[0] == 'x' && isspace(next[1]))) {
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const wchar_t *start;
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start = next;
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while ((next[0] >= 'a' && next[0] <= 'z') || (next[0] >= '0' && next[0] <= '9') ||
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(next[0] == '_'))
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next++;
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if (next_[0] >= 'a' && next_[0] <= 'z' && !(next_[0] == 'x' && isspace(next_[1]))) {
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const wchar_t *start = next_;
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while ((next_[0] >= 'a' && next_[0] <= 'z') ||
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(next_[0] >= '0' && next_[0] <= '9') || (next_[0] == '_'))
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next_++;
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const te_builtin *var = find_builtin(start, next - start);
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const te_builtin *var = find_builtin(start, next_ - start);
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if (var) {
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switch (var->type) {
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case TE_FUNCTION0:
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case TE_FUNCTION1:
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case TE_FUNCTION2:
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type = var->type;
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function = var->address;
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break;
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}
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} else if (type != TOK_ERROR || error == TE_ERROR_UNKNOWN) {
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type_ = TOK_FUNCTION;
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current_ = var->fn;
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} else if (type_ != TOK_ERROR || error_ == TE_ERROR_UNKNOWN) {
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// Our error is more specific, so it takes precedence.
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type = TOK_ERROR;
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error = TE_ERROR_UNKNOWN_FUNCTION;
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type_ = TOK_ERROR;
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error_ = TE_ERROR_UNKNOWN_FUNCTION;
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}
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} else {
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/* Look for an operator or special character. */
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switch (next++[0]) {
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// The "te_fun2" casts are necessary to pick the right overload.
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switch (next_++[0]) {
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case '+':
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type = TOK_INFIX;
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function = reinterpret_cast<void *>(static_cast<te_fun2>(add));
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type_ = TOK_INFIX;
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current_ = add;
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break;
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case '-':
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type = TOK_INFIX;
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function = reinterpret_cast<void *>(static_cast<te_fun2>(sub));
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type_ = TOK_INFIX;
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current_ = sub;
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break;
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case 'x':
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case '*':
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// We've already checked for whitespace above.
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type = TOK_INFIX;
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function = reinterpret_cast<void *>(static_cast<te_fun2>(mul));
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type_ = TOK_INFIX;
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current_ = mul;
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break;
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case '/':
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type = TOK_INFIX;
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function = reinterpret_cast<void *>(static_cast<te_fun2>(divide));
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type_ = TOK_INFIX;
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current_ = divide;
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break;
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case '^':
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type = TOK_INFIX;
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function = reinterpret_cast<void *>(static_cast<te_fun2>(pow));
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type_ = TOK_INFIX;
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current_ = pow;
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break;
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case '%':
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type = TOK_INFIX;
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function = reinterpret_cast<void *>(static_cast<te_fun2>(fmod));
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type_ = TOK_INFIX;
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current_ = fmod;
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break;
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case '(':
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type = TOK_OPEN;
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type_ = TOK_OPEN;
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break;
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case ')':
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type = TOK_CLOSE;
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type_ = TOK_CLOSE;
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break;
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case ',':
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type = TOK_SEP;
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type_ = TOK_SEP;
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break;
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case ' ':
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case '\t':
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@ -355,124 +337,121 @@ void state::next_token() {
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case '&':
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case '|':
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case '!':
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type = TOK_ERROR;
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error = TE_ERROR_LOGICAL_OPERATOR;
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type_ = TOK_ERROR;
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error_ = TE_ERROR_LOGICAL_OPERATOR;
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break;
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default:
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type = TOK_ERROR;
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error = TE_ERROR_MISSING_OPERATOR;
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type_ = TOK_ERROR;
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error_ = TE_ERROR_MISSING_OPERATOR;
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break;
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}
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}
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}
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} while (type == TOK_NULL);
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} while (type_ == TOK_NULL);
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}
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te_expr_t *state::base() {
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double state::base() {
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/* <base> = <constant> | <function-0> {"(" ")"} | <function-1> <power> |
|
||||
* <function-X> "(" <expr> {"," <expr>} ")" | "(" <list> ")" */
|
||||
te_expr_t *ret;
|
||||
int arity;
|
||||
|
||||
auto previous = start;
|
||||
auto next = this->next;
|
||||
switch (type) {
|
||||
case TOK_NUMBER:
|
||||
ret = new_expr(TE_CONSTANT, nullptr);
|
||||
ret->value = value;
|
||||
auto previous = start_;
|
||||
auto next = next_;
|
||||
switch (type_) {
|
||||
case TOK_NUMBER: {
|
||||
auto val = current_();
|
||||
next_token();
|
||||
if (type == TOK_NUMBER || type == TE_FUNCTION0) {
|
||||
if (type_ == TOK_NUMBER || type_ == TOK_FUNCTION) {
|
||||
// Two numbers after each other:
|
||||
// math '5 2'
|
||||
// math '3 pi'
|
||||
// (of course 3 pi could also be interpreted as 3 x pi)
|
||||
type = TOK_ERROR;
|
||||
error = TE_ERROR_MISSING_OPERATOR;
|
||||
type_ = TOK_ERROR;
|
||||
error_ = TE_ERROR_MISSING_OPERATOR;
|
||||
// The error should be given *between*
|
||||
// the last two tokens.
|
||||
// Since these are two separate numbers there is at least
|
||||
// one space between.
|
||||
start = previous;
|
||||
this->next = next + 1;
|
||||
start_ = previous;
|
||||
next_ = next + 1;
|
||||
}
|
||||
break;
|
||||
return val;
|
||||
}
|
||||
|
||||
case TE_FUNCTION0:
|
||||
ret = new_expr(type, nullptr);
|
||||
ret->fun0 = reinterpret_cast<te_fun0>(function);
|
||||
next_token();
|
||||
if (type == TOK_OPEN) {
|
||||
next_token();
|
||||
if (type == TOK_CLOSE) {
|
||||
next_token();
|
||||
} else if (type != TOK_ERROR || error == TE_ERROR_UNKNOWN) {
|
||||
type = TOK_ERROR;
|
||||
error = TE_ERROR_MISSING_CLOSING_PAREN;
|
||||
}
|
||||
}
|
||||
break;
|
||||
|
||||
case TE_FUNCTION1:
|
||||
case TE_FUNCTION2: {
|
||||
arity = get_arity(type);
|
||||
|
||||
ret = new_expr(type, nullptr);
|
||||
ret->fun0 = reinterpret_cast<te_fun0>(function);
|
||||
case TOK_FUNCTION: {
|
||||
auto fn = current_;
|
||||
int arity = fn.arity();
|
||||
next_token();
|
||||
|
||||
bool have_open = false;
|
||||
if (type == TOK_OPEN) {
|
||||
const bool have_open = type_ == TOK_OPEN;
|
||||
if (have_open) {
|
||||
// If we *have* an opening parenthesis,
|
||||
// we need to consume it and
|
||||
// expect a closing one.
|
||||
have_open = true;
|
||||
next_token();
|
||||
}
|
||||
|
||||
if (arity == 0) {
|
||||
if (have_open) {
|
||||
if (type_ == TOK_CLOSE) {
|
||||
next_token();
|
||||
} else if (type_ != TOK_ERROR || error_ == TE_ERROR_UNKNOWN) {
|
||||
type_ = TOK_ERROR;
|
||||
error_ = TE_ERROR_MISSING_CLOSING_PAREN;
|
||||
break;
|
||||
}
|
||||
}
|
||||
return fn();
|
||||
}
|
||||
|
||||
std::vector<double> parameters;
|
||||
int i;
|
||||
for (i = 0; i < arity; i++) {
|
||||
ret->parameters[i] = expr();
|
||||
if (type != TOK_SEP) {
|
||||
parameters.push_back(expr());
|
||||
if (type_ != TOK_SEP) {
|
||||
break;
|
||||
}
|
||||
next_token();
|
||||
}
|
||||
|
||||
if (!have_open && i == arity - 1) {
|
||||
break;
|
||||
return fn(parameters);
|
||||
}
|
||||
|
||||
if (have_open && type == TOK_CLOSE && i == arity - 1) {
|
||||
if (have_open && type_ == TOK_CLOSE && i == arity - 1) {
|
||||
// We have an opening and a closing paren, consume the closing one and done.
|
||||
next_token();
|
||||
} else if (type != TOK_ERROR || error == TE_ERROR_UNEXPECTED_TOKEN) {
|
||||
return fn(parameters);
|
||||
}
|
||||
if (type_ != TOK_ERROR || error_ == TE_ERROR_UNEXPECTED_TOKEN) {
|
||||
// If we had the right number of arguments, we're missing a closing paren.
|
||||
if (have_open && i == arity - 1 && type != TOK_ERROR) {
|
||||
error = TE_ERROR_MISSING_CLOSING_PAREN;
|
||||
if (have_open && i == arity - 1 && type_ != TOK_ERROR) {
|
||||
error_ = TE_ERROR_MISSING_CLOSING_PAREN;
|
||||
} else {
|
||||
// Otherwise we complain about the number of arguments *first*,
|
||||
// a closing parenthesis should be more obvious.
|
||||
error = i < arity ? TE_ERROR_TOO_FEW_ARGS : TE_ERROR_TOO_MANY_ARGS;
|
||||
error_ = i < arity ? TE_ERROR_TOO_FEW_ARGS : TE_ERROR_TOO_MANY_ARGS;
|
||||
}
|
||||
type = TOK_ERROR;
|
||||
type_ = TOK_ERROR;
|
||||
}
|
||||
|
||||
break;
|
||||
}
|
||||
|
||||
case TOK_OPEN:
|
||||
case TOK_OPEN: {
|
||||
next_token();
|
||||
ret = expr();
|
||||
if (type == TOK_CLOSE) {
|
||||
auto ret = expr();
|
||||
if (type_ == TOK_CLOSE) {
|
||||
next_token();
|
||||
} else if (type != TOK_ERROR && type != TOK_END && error == TE_ERROR_NONE) {
|
||||
type = TOK_ERROR;
|
||||
error = TE_ERROR_TOO_MANY_ARGS;
|
||||
} else if (type != TOK_ERROR || error == TE_ERROR_UNKNOWN) {
|
||||
type = TOK_ERROR;
|
||||
error = TE_ERROR_MISSING_CLOSING_PAREN;
|
||||
return ret;
|
||||
}
|
||||
if (type_ != TOK_ERROR && type_ != TOK_END && error_ == TE_ERROR_NONE) {
|
||||
type_ = TOK_ERROR;
|
||||
error_ = TE_ERROR_TOO_MANY_ARGS;
|
||||
} else if (type_ != TOK_ERROR || error_ == TE_ERROR_UNKNOWN) {
|
||||
type_ = TOK_ERROR;
|
||||
error_ = TE_ERROR_MISSING_CLOSING_PAREN;
|
||||
}
|
||||
break;
|
||||
}
|
||||
|
||||
case TOK_END:
|
||||
// The expression ended before we expected it.
|
||||
|
|
@ -480,178 +459,67 @@ te_expr_t *state::base() {
|
|||
// This means we have too few things.
|
||||
// Instead of introducing another error, just call it
|
||||
// "too few args".
|
||||
ret = new_expr(0, nullptr);
|
||||
type = TOK_ERROR;
|
||||
error = TE_ERROR_TOO_FEW_ARGS;
|
||||
ret->value = NAN;
|
||||
type_ = TOK_ERROR;
|
||||
error_ = TE_ERROR_TOO_FEW_ARGS;
|
||||
break;
|
||||
default:
|
||||
ret = new_expr(0, nullptr);
|
||||
if (type != TOK_ERROR || error == TE_ERROR_UNKNOWN) {
|
||||
type = TOK_ERROR;
|
||||
error = TE_ERROR_UNEXPECTED_TOKEN;
|
||||
if (type_ != TOK_ERROR || error_ == TE_ERROR_UNKNOWN) {
|
||||
type_ = TOK_ERROR;
|
||||
error_ = TE_ERROR_UNEXPECTED_TOKEN;
|
||||
}
|
||||
ret->value = NAN;
|
||||
break;
|
||||
}
|
||||
|
||||
return ret;
|
||||
return NAN;
|
||||
}
|
||||
|
||||
te_expr_t *state::power() {
|
||||
double state::power() {
|
||||
/* <power> = {("-" | "+")} <base> */
|
||||
int sign = 1;
|
||||
while (type == TOK_INFIX && (function == add || function == sub)) {
|
||||
if (function == sub) sign = -sign;
|
||||
while (type_ == TOK_INFIX && (current_ == add || current_ == sub)) {
|
||||
if (current_ == sub) sign = -sign;
|
||||
next_token();
|
||||
}
|
||||
|
||||
te_expr_t *ret;
|
||||
|
||||
if (sign == 1) {
|
||||
ret = base();
|
||||
} else {
|
||||
ret = NEW_EXPR(TE_FUNCTION1, base());
|
||||
ret->fun1 = negate;
|
||||
}
|
||||
|
||||
return ret;
|
||||
return sign * base();
|
||||
}
|
||||
|
||||
te_expr_t *state::factor() {
|
||||
double state::factor() {
|
||||
/* <factor> = <power> {"^" <power>} */
|
||||
te_expr_t *ret = power();
|
||||
auto ret = power();
|
||||
|
||||
te_expr_t *insertion = nullptr;
|
||||
|
||||
while (type == TOK_INFIX && (function == reinterpret_cast<void *>(static_cast<te_fun2>(pow)))) {
|
||||
auto t = reinterpret_cast<te_fun2>(function);
|
||||
if (type_ == TOK_INFIX && current_ == pow) {
|
||||
next_token();
|
||||
|
||||
if (insertion) {
|
||||
/* Make exponentiation go right-to-left. */
|
||||
te_expr_t *insert = NEW_EXPR(TE_FUNCTION2, insertion->parameters[1], power());
|
||||
insert->fun2 = t;
|
||||
insertion->parameters[1] = insert;
|
||||
insertion = insert;
|
||||
} else {
|
||||
ret = NEW_EXPR(TE_FUNCTION2, ret, power());
|
||||
ret->fun2 = t;
|
||||
insertion = ret;
|
||||
}
|
||||
ret = pow(ret, factor());
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
te_expr_t *state::term() {
|
||||
double state::term() {
|
||||
/* <term> = <factor> {("*" | "/" | "%") <factor>} */
|
||||
te_expr_t *ret = factor();
|
||||
|
||||
while (type == TOK_INFIX &&
|
||||
(function == reinterpret_cast<void *>(static_cast<te_fun2>(mul)) ||
|
||||
function == reinterpret_cast<void *>(static_cast<te_fun2>(divide)) ||
|
||||
function == reinterpret_cast<void *>(static_cast<te_fun2>(fmod)))) {
|
||||
auto t = reinterpret_cast<te_fun2>(function);
|
||||
auto ret = factor();
|
||||
while (type_ == TOK_INFIX && (current_ == mul || current_ == divide || current_ == fmod)) {
|
||||
auto fn = current_;
|
||||
next_token();
|
||||
ret = NEW_EXPR(TE_FUNCTION2, ret, factor());
|
||||
ret->fun2 = t;
|
||||
ret = fn(ret, factor());
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
te_expr_t *state::expr() {
|
||||
double state::expr() {
|
||||
/* <expr> = <term> {("+" | "-") <term>} */
|
||||
te_expr_t *ret = term();
|
||||
|
||||
while (type == TOK_INFIX && (function == add || function == sub)) {
|
||||
auto t = reinterpret_cast<te_fun2>(function);
|
||||
auto ret = term();
|
||||
while (type_ == TOK_INFIX && (current_ == add || current_ == sub)) {
|
||||
auto fn = current_;
|
||||
next_token();
|
||||
ret = NEW_EXPR(TE_FUNCTION2, ret, term());
|
||||
ret->fun2 = t;
|
||||
ret = fn(ret, term());
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
#define M(e) te_eval(n->parameters[e])
|
||||
|
||||
/* Evaluates the expression. */
|
||||
static double te_eval(const te_expr_t *n) {
|
||||
if (!n) return NAN;
|
||||
|
||||
switch (n->type) {
|
||||
case TE_CONSTANT:
|
||||
return n->value;
|
||||
case TE_FUNCTION0:
|
||||
return n->fun0();
|
||||
case TE_FUNCTION1:
|
||||
return n->fun1(M(0));
|
||||
case TE_FUNCTION2:
|
||||
return n->fun2(M(0), M(1));
|
||||
default:
|
||||
return NAN;
|
||||
}
|
||||
}
|
||||
|
||||
#undef M
|
||||
|
||||
static void optimize(te_expr_t *n) {
|
||||
/* Evaluates as much as possible. */
|
||||
if (!n || n->type == TE_CONSTANT) return;
|
||||
|
||||
const int arity = get_arity(n->type);
|
||||
bool known = true;
|
||||
for (int i = 0; i < arity; ++i) {
|
||||
optimize(n->parameters[i]);
|
||||
if ((n->parameters[i])->type != TE_CONSTANT) {
|
||||
known = false;
|
||||
}
|
||||
}
|
||||
if (known) {
|
||||
const double value = te_eval(n);
|
||||
te_free_parameters(n);
|
||||
n->type = TE_CONSTANT;
|
||||
n->value = value;
|
||||
}
|
||||
}
|
||||
|
||||
/* Parses the input expression. */
|
||||
/* Returns NULL on error. */
|
||||
static te_expr_t *te_compile(const wchar_t *expression, te_error_t *error) {
|
||||
state s{expression};
|
||||
|
||||
te_expr_t *root = s.expr();
|
||||
|
||||
if (s.type != TOK_END) {
|
||||
te_free(root);
|
||||
if (error) {
|
||||
error->position = (s.next - s.start) + 1;
|
||||
if (s.error != TE_ERROR_NONE) {
|
||||
error->type = s.error;
|
||||
} else {
|
||||
// If we're not at the end but there's no error, then that means we have a
|
||||
// superfluous token that we have no idea what to do with.
|
||||
error->type = TE_ERROR_TOO_MANY_ARGS;
|
||||
}
|
||||
}
|
||||
return nullptr;
|
||||
} else {
|
||||
optimize(root);
|
||||
if (error) error->position = 0;
|
||||
return root;
|
||||
}
|
||||
}
|
||||
|
||||
double te_interp(const wchar_t *expression, te_error_t *error) {
|
||||
te_expr_t *n = te_compile(expression, error);
|
||||
double ret;
|
||||
if (n) {
|
||||
ret = te_eval(n);
|
||||
te_free(n);
|
||||
} else {
|
||||
ret = NAN;
|
||||
}
|
||||
state s{expression};
|
||||
double ret = s.eval();
|
||||
if (error) *error = s.error();
|
||||
return ret;
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in a new issue