cground/src/interpreter.c

#include "interpreter.h"
#include "parser.h"
#include "types.h"
#include "include/uthash.h"
#include <stdlib.h>

int currentInstruction = 0;

void runtimeError(GroundRuntimeError error, char* what, GroundInstruction* where, int whereLine) {
    printf("Ground runtime error:\n  ErrorType: ");
    switch (error) {
        case ARG_TYPE_MISMATCH: {
            printf("ArgTypeMismatch");
            break;
        }
        case TOO_FEW_ARGS: {
            printf("TooFewArgs");
            break;
        }
        case TOO_MANY_ARGS: {
            printf("TooManyArgs");
            break;
        }
        default:
        case FIXME: {
            printf("FIXME (please report issue to https://chsp.au/ground/cground)");
        }
    }
    printf("\n");
    if (what != NULL) {
        printf("  ErrorContext: %s\n", what);
    }
    if (where != NULL) {
        printf("  ErrorInstruction: ");
        printGroundInstruction(where);
        printf("\n");
    }
    if (whereLine > -1) {
        printf("  ErrorLine: %d\n", whereLine + 1);
    }
    exit(1);
}

void addLabel(GroundLabel **head, const char *id, int data) {
    GroundLabel* item = malloc(sizeof(GroundLabel));
    snprintf(item->id, MAX_ID_LEN, "%s", id);
    item->lineNum = data;
    HASH_ADD_STR(*head, id, item);
}

GroundLabel* findLabel(GroundLabel* head, const char *id) {
    GroundLabel *item;
    HASH_FIND_STR(head, id, item);
    return item;
}

void deleteLabel(GroundLabel** head, GroundLabel *item) {
    HASH_DEL(*head, item);
    free(item);
}

void addVariable(GroundVariable **head, const char *id, GroundValue data) {
    GroundVariable* item = malloc(sizeof(GroundVariable));
    snprintf(item->id, MAX_ID_LEN, "%s", id);
    item->value = data;
    HASH_ADD_STR(*head, id, item);
}

GroundVariable* findVariable(GroundVariable* head, const char *id) {
    GroundVariable *item;
    HASH_FIND_STR(head, id, item);
    return item;
}

void deleteVariable(GroundVariable** head, GroundVariable *item) {
    HASH_DEL(*head, item);
    free(item);
}

void interpretGroundProgram(GroundProgram* in) {
    GroundLabel* labels = NULL;
    GroundVariable* variables = NULL;

    GroundScope scope;
    scope.labels = &labels;
    scope.variables = &variables;
    // Preprocess all labels
    for (int i = 0; i < in->size; i++) {
        if (in->instructions[i].type == CREATELABEL) {
            addLabel(scope.labels, in->instructions[i].args.args[0].value.refName, i);
        }
    }
    while (currentInstruction < in->size) {
        interpretGroundInstruction(&in->instructions[currentInstruction], &scope);
        currentInstruction++;
    }
    
}

void interpretGroundInstruction(GroundInstruction* in, GroundScope* scope) {
    switch (in->type) {
        // We can safely ignore any CREATELABEL instructions, these have been preprocessed
        case CREATELABEL: {
            break;
        }
        case IF: {
            if (in->args.length < 2) {
                runtimeError(TOO_FEW_ARGS, "Expecting 2 arguments", in, currentInstruction);
            }
            if (in->args.length > 2) {
                runtimeError(TOO_MANY_ARGS, "Expecting 2 arguments", in, currentInstruction);
            }
            if (in->args.args[0].type != VALUE || in->args.args[0].value.value.type != BOOL) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a bool for arg 0", in, currentInstruction);
            }
            if (in->args.args[1].type != LINEREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a LineRef for arg 1", in, currentInstruction);
            }

            if (in->args.args[0].value.value.data.boolVal) {
                GroundLabel* label = findLabel(*scope->labels, in->args.args[1].value.refName);
                if (label) {
                    currentInstruction = label->lineNum;
                } else {
                    runtimeError(UNKNOWN_LABEL, NULL, in, currentInstruction);
                }
            }
            break;
        }
        case JUMP: {
            if (in->args.length < 1) {
                runtimeError(TOO_FEW_ARGS, "Expecting 1 argument", in, currentInstruction);
            }
            if (in->args.length > 1) {
                runtimeError(TOO_MANY_ARGS, "Expecting 1 argument", in, currentInstruction);
            }
            if (in->args.args[0].type != LINEREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a LineRef for arg 1", in, currentInstruction);
            }

            GroundLabel* label = findLabel(*scope->labels, in->args.args[0].value.refName);
            if (label) {
                currentInstruction = label->lineNum;
            } else {
                runtimeError(UNKNOWN_LABEL, NULL, in, currentInstruction);
            }
            break;
        }
        case END: {
            if (in->args.length < 1 || in->args.args[0].type != VALUE || in->args.args[0].value.value.type != INT) {
                exit(0);
            } else {
                exit(in->args.args[0].value.value.data.intVal);
            }
            break;
        }
        case PRINT: {
            if (in->args.length < 1) {
                runtimeError(TOO_FEW_ARGS, NULL, in, currentInstruction);
            }
            for (int i = 0; i < in->args.length; i++) {
                printGroundArg(&in->args.args[i]);
                printf(" ");
            }
            break;
        }
        case PRINTLN: {
            if (in->args.length < 1) {
                runtimeError(TOO_FEW_ARGS, NULL, in, currentInstruction);
            }
            for (int i = 0; i < in->args.length; i++) {
                printGroundArg(&in->args.args[i]);
                printf(" ");
            }
            printf("\n");
            break;
        }
        default: {
            runtimeError(FIXME, "Currently unimplemented instruction", in, currentInstruction);
        }
    }

}