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Copy pathstrings.rs
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Copy pathstrings.rs
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1364 lines (1198 loc) · 46.3 KB
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// EndBASIC
// Copyright 2020 Julio Merino
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//! String functions for EndBASIC.
use endbasic_core::{
AnyValueSyntax, ArgSep, ArgSepSyntax, CallError, CallResult, Callable, CallableMetadata,
CallableMetadataBuilder, ExprType, RequiredValueSyntax, Scope, SingularArgSyntax, VarArgTag,
};
use std::borrow::Cow;
use std::cmp::min;
use std::convert::TryFrom;
use std::rc::Rc;
use crate::MachineBuilder;
/// Category description for all symbols provided by this module.
const CATEGORY: &str = "String and character functions";
/// Formats a boolean `b` for display.
pub fn format_boolean(b: bool) -> &'static str {
if b { "TRUE" } else { "FALSE" }
}
/// Parses a string `s` as a boolean.
pub fn parse_boolean(s: &str) -> Result<bool, String> {
let raw = s.to_uppercase();
if raw == "TRUE" || raw == "YES" || raw == "Y" {
Ok(true)
} else if raw == "FALSE" || raw == "NO" || raw == "N" {
Ok(false)
} else {
Err(format!("Invalid boolean literal {}", s))
}
}
/// Formats a double `d` for display.
pub fn format_double(d: f64) -> String {
if !d.is_nan() && d.is_sign_negative() { d.to_string() } else { format!(" {}", d) }
}
/// Parses a string `s` as a double.
pub fn parse_double(s: &str) -> Result<f64, String> {
match s.parse::<f64>() {
Ok(d) => Ok(d),
Err(_) => Err(format!("Invalid double-precision floating point literal {}", s)),
}
}
/// Formats an integer `i` for display.
pub fn format_integer(i: i32) -> String {
if i.is_negative() { i.to_string() } else { format!(" {}", i) }
}
/// Parses a string `s` as an integer.
pub fn parse_integer(s: &str) -> Result<i32, String> {
match s.parse::<i32>() {
Ok(d) => Ok(d),
Err(_) => Err(format!("Invalid integer literal {}", s)),
}
}
/// Returns the byte offset of the given character position within `s`.
fn char_index_to_byte_index(s: &str, char_index: usize) -> usize {
s.char_indices().nth(char_index).map(|(i, _)| i).unwrap_or(s.len())
}
/// Returns the number of characters before the given byte offset within `s`.
fn byte_index_to_char_index(s: &str, byte_index: usize) -> usize {
s[..byte_index].chars().count()
}
/// Returns the number of characters in `s`.
fn char_len(s: &str) -> usize {
s.chars().count()
}
/// Returns the substring of `s` within the given character range.
fn slice_by_char_range(s: &str, start: usize, end: usize) -> &str {
let start = char_index_to_byte_index(s, start);
let end = char_index_to_byte_index(s, end);
&s[start..end]
}
/// Parses the numeric prefix in `s` according to BASIC's `VAL` rules.
fn parse_numeric_prefix(s: &str) -> f64 {
let s = s.trim_start();
let bytes = s.as_bytes();
let mut i = 0;
if let Some(b'+' | b'-') = bytes.first().copied() {
i += 1;
}
let int_start = i;
while i < bytes.len() && bytes[i].is_ascii_digit() {
i += 1;
}
let have_int = i > int_start;
if i < bytes.len() && bytes[i] == b'.' {
i += 1;
let frac_start = i;
while i < bytes.len() && bytes[i].is_ascii_digit() {
i += 1;
}
if !have_int && i == frac_start {
return 0.0;
}
} else if !have_int {
return 0.0;
}
let mut end = i;
if i < bytes.len() && matches!(bytes[i], b'e' | b'E') {
let mut j = i + 1;
if j < bytes.len() && matches!(bytes[j], b'+' | b'-') {
j += 1;
}
let exp_start = j;
while j < bytes.len() && bytes[j].is_ascii_digit() {
j += 1;
}
if j > exp_start {
end = j;
}
}
s[..end].parse().expect("numeric prefix must parse")
}
/// The `ASC` function.
pub struct AscFunction {
metadata: Rc<CallableMetadata>,
}
impl AscFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("ASC")
.with_return_type(ExprType::Integer)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("char"), vtype: ExprType::Text },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description(
"Returns the UTF character code of the input character.
The input char$ argument is a string that must be 1-character long.
This is called ASC for historical reasons but supports more than just ASCII characters in this \
implementation of BASIC.
See CHR$() for the inverse of this function.",
)
.build(),
})
}
}
impl Callable for AscFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let s = scope.get_string(0);
let mut chars = s.chars();
let ch = match chars.next() {
Some(ch) => ch,
None => {
return Err(CallError::Syntax(
scope.get_pos(0),
format!("Input string \"{}\" must be 1-character long", s),
));
}
};
if chars.next().is_some() {
return Err(CallError::Syntax(
scope.get_pos(0),
format!("Input string \"{}\" must be 1-character long", s),
));
}
let ch = if cfg!(debug_assertions) {
i32::try_from(ch as u32).expect("Unicode code points end at U+10FFFF")
} else {
ch as i32
};
scope.return_integer(ch)
}
}
/// The `CHR` function.
pub struct ChrFunction {
metadata: Rc<CallableMetadata>,
}
impl ChrFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("CHR")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("code"),
vtype: ExprType::Integer,
},
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description(
"Returns the UTF character that corresponds to the given code.
See ASC%() for the inverse of this function.",
)
.build(),
})
}
}
impl Callable for ChrFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let i = scope.get_integer(0);
if i < 0 {
return Err(CallError::Syntax(
scope.get_pos(0),
format!("Character code {} must be positive", i),
));
}
let code = i as u32;
match char::from_u32(code) {
Some(ch) => scope.return_string(format!("{}", ch)),
None => {
Err(CallError::Syntax(scope.get_pos(0), format!("Invalid character code {}", code)))
}
}
}
}
/// The `INSTR` function.
pub struct InstrFunction {
metadata: Rc<CallableMetadata>,
}
impl InstrFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("INSTR")
.with_return_type(ExprType::Integer)
.with_syntax(&[
(
&[
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("expr"),
vtype: ExprType::Text,
},
ArgSepSyntax::Exactly(ArgSep::Long),
),
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("search"),
vtype: ExprType::Text,
},
ArgSepSyntax::End,
),
],
None,
),
(
&[
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("start"),
vtype: ExprType::Integer,
},
ArgSepSyntax::Exactly(ArgSep::Long),
),
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("expr"),
vtype: ExprType::Text,
},
ArgSepSyntax::Exactly(ArgSep::Long),
),
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("search"),
vtype: ExprType::Text,
},
ArgSepSyntax::End,
),
],
None,
),
])
.with_category(CATEGORY)
.with_description(
"Searches for a substring within another string.
Returns the 1-indexed position of search$ within expr$, or 0 if not found.
If start% is given, the search begins at that 1-indexed character position.",
)
.build(),
})
}
}
impl Callable for InstrFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert!((2..=3).contains(&scope.nargs()));
let (start, sarg, searcharg) =
if scope.nargs() == 2 { (1, 0, 1) } else { (scope.get_integer(0), 1, 2) };
let s = scope.get_string(sarg);
let search = scope.get_string(searcharg);
if start <= 0 {
return Err(CallError::Syntax(scope.get_pos(0), "start% must be positive".to_owned()));
}
let start = (start - 1) as usize;
let slen = s.chars().count();
if start > slen {
return scope.return_integer(0);
}
if search.is_empty() {
return scope.return_integer((start + 1) as i32);
}
let start_byte = char_index_to_byte_index(s, start);
let position = match s[start_byte..].find(search) {
Some(offset) => {
let byte_index = start_byte + offset;
(byte_index_to_char_index(s, byte_index) + 1) as i32
}
None => 0,
};
scope.return_integer(position)
}
}
/// The `LCASE` function.
pub struct LcaseFunction {
metadata: Rc<CallableMetadata>,
}
impl LcaseFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("LCASE")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("expr"), vtype: ExprType::Text },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description(
"Returns a copy of a string with all letters converted to lowercase.",
)
.build(),
})
}
}
impl Callable for LcaseFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let s = scope.get_string(0).to_owned();
scope.return_string(s.to_lowercase())
}
}
/// The `LEFT` function.
pub struct LeftFunction {
metadata: Rc<CallableMetadata>,
}
impl LeftFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("LEFT")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("expr"),
vtype: ExprType::Text,
},
ArgSepSyntax::Exactly(ArgSep::Long),
),
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("n"),
vtype: ExprType::Integer,
},
ArgSepSyntax::End,
),
],
None,
)])
.with_category(CATEGORY)
.with_description(
"Returns a given number of characters from the left side of a string.
If n% is 0, returns an empty string.
If n% is greater than or equal to the number of characters in expr$, returns expr$.",
)
.build(),
})
}
}
impl Callable for LeftFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(2, scope.nargs());
let s = scope.get_string(0).to_owned();
let n = scope.get_integer(1);
if n < 0 {
Err(CallError::Syntax(scope.get_pos(1), "n% cannot be negative".to_owned()))
} else {
let n = min(char_len(&s), n as usize);
scope.return_string(slice_by_char_range(&s, 0, n).to_owned())
}
}
}
/// The `LEN` function.
pub struct LenFunction {
metadata: Rc<CallableMetadata>,
}
impl LenFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("LEN")
.with_return_type(ExprType::Integer)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("expr"), vtype: ExprType::Text },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description("Returns the length of the string in expr$.")
.build(),
})
}
}
impl Callable for LenFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let s = scope.get_string(0);
let len = i32::try_from(char_len(s))
.map_err(|_| CallError::Eval("String too long".to_owned()))?;
scope.return_integer(len)
}
}
/// The `LTRIM` function.
pub struct LtrimFunction {
metadata: Rc<CallableMetadata>,
}
impl LtrimFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("LTRIM")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("expr"), vtype: ExprType::Text },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description("Returns a copy of a string with leading whitespace removed.")
.build(),
})
}
}
impl Callable for LtrimFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let s = scope.get_string(0).to_owned();
scope.return_string(s.trim_start().to_owned())
}
}
/// The `MID` function.
pub struct MidFunction {
metadata: Rc<CallableMetadata>,
}
impl MidFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("MID")
.with_return_type(ExprType::Text)
.with_syntax(&[
(
&[
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("expr"),
vtype: ExprType::Text,
},
ArgSepSyntax::Exactly(ArgSep::Long),
),
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("start"),
vtype: ExprType::Integer,
},
ArgSepSyntax::End,
),
],
None,
),
(
&[
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("expr"),
vtype: ExprType::Text,
},
ArgSepSyntax::Exactly(ArgSep::Long),
),
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("start"),
vtype: ExprType::Integer,
},
ArgSepSyntax::Exactly(ArgSep::Long),
),
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("length"),
vtype: ExprType::Integer,
},
ArgSepSyntax::End,
),
],
None,
),
])
.with_category(CATEGORY)
.with_description(
"Returns a portion of a string.
start% indicates the starting position of the substring to extract and it is 1-indexed.
length% indicates the number of characters to extract and, if not specified, defaults to extracting
until the end of the string.",
)
.build(),
})
}
}
impl Callable for MidFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert!((2..=3).contains(&scope.nargs()));
let s = scope.get_string(0).to_owned();
let start = scope.get_integer(1);
let lengtharg = if scope.nargs() == 3 { Some(scope.get_integer(2)) } else { None };
if start < 0 {
return Err(CallError::Syntax(
scope.get_pos(1),
"start% cannot be negative".to_owned(),
));
}
let slen = char_len(&s);
let start = min(slen, start as usize);
let end = if let Some(length) = lengtharg {
if length < 0 {
return Err(CallError::Syntax(
scope.get_pos(2),
"length% cannot be negative".to_owned(),
));
}
min(start + (length as usize), slen)
} else {
slen
};
scope.return_string(slice_by_char_range(&s, start, end).to_owned())
}
}
/// The `RIGHT` function.
pub struct RightFunction {
metadata: Rc<CallableMetadata>,
}
impl RightFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("RIGHT")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("expr"),
vtype: ExprType::Text,
},
ArgSepSyntax::Exactly(ArgSep::Long),
),
SingularArgSyntax::RequiredValue(
RequiredValueSyntax {
name: Cow::Borrowed("n"),
vtype: ExprType::Integer,
},
ArgSepSyntax::End,
),
],
None,
)])
.with_category(CATEGORY)
.with_description(
"Returns a given number of characters from the right side of a string.
If n% is 0, returns an empty string.
If n% is greater than or equal to the number of characters in expr$, returns expr$.",
)
.build(),
})
}
}
impl Callable for RightFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(2, scope.nargs());
let s = scope.get_string(0).to_owned();
let n = scope.get_integer(1);
if n < 0 {
Err(CallError::Syntax(scope.get_pos(1), "n% cannot be negative".to_owned()))
} else {
let slen = char_len(&s);
let n = min(slen, n as usize);
scope.return_string(slice_by_char_range(&s, slen - n, slen).to_owned())
}
}
}
/// The `RTRIM` function.
pub struct RtrimFunction {
metadata: Rc<CallableMetadata>,
}
impl RtrimFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("RTRIM")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("expr"), vtype: ExprType::Text },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description("Returns a copy of a string with trailing whitespace removed.")
.build(),
})
}
}
impl Callable for RtrimFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let s = scope.get_string(0).to_owned();
scope.return_string(s.trim_end().to_owned())
}
}
/// The `SPACE` function.
pub struct SpaceFunction {
metadata: Rc<CallableMetadata>,
}
impl SpaceFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("SPACE")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("n"), vtype: ExprType::Integer },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description(
"Returns a string that contains n% space characters.
If n% is 0, returns an empty string.",
)
.build(),
})
}
}
impl Callable for SpaceFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let n = scope.get_integer(0);
if n < 0 {
Err(CallError::Syntax(scope.get_pos(0), "n% cannot be negative".to_owned()))
} else {
scope.return_string(" ".repeat(n as usize))
}
}
}
/// The `STR` function.
pub struct StrFunction {
metadata: Rc<CallableMetadata>,
}
impl StrFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("STR")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[SingularArgSyntax::AnyValue(
AnyValueSyntax { name: Cow::Borrowed("expr"), allow_missing: false },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description(
"Formats a scalar value as a string.
If expr evaluates to a string, this returns the string unmodified.
If expr evaluates to a boolean, this returns the strings FALSE or TRUE.
If expr evaluates to a number, this returns a string with the textual representation of the \
number. If the number does NOT have a negative sign, the resulting string has a single space \
in front of it.
To obtain a clean representation of expr as a string without any artificial whitespace characters \
in it, do LTRIM$(STR$(expr)).",
)
.build(),
})
}
}
impl Callable for StrFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(2, scope.nargs());
match scope.get_type(0) {
VarArgTag::Immediate(_, ExprType::Boolean) => {
let b = scope.get_boolean(1);
scope.return_string(format_boolean(b).to_owned())
}
VarArgTag::Immediate(_, ExprType::Double) => {
let d = scope.get_double(1);
scope.return_string(format_double(d))
}
VarArgTag::Immediate(_, ExprType::Integer) => {
let i = scope.get_integer(1);
scope.return_string(format_integer(i))
}
VarArgTag::Immediate(_, ExprType::Text) => {
let s = scope.get_string(1).to_owned();
scope.return_string(s)
}
VarArgTag::Missing(..) | VarArgTag::Pointer(..) => unreachable!(),
}
}
}
/// The `TRIM` function.
pub struct TrimFunction {
metadata: Rc<CallableMetadata>,
}
impl TrimFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("TRIM")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("expr"), vtype: ExprType::Text },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description(
"Returns a copy of a string with leading and trailing whitespace removed.",
)
.build(),
})
}
}
impl Callable for TrimFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let s = scope.get_string(0).to_owned();
scope.return_string(s.trim().to_owned())
}
}
/// The `UCASE` function.
pub struct UcaseFunction {
metadata: Rc<CallableMetadata>,
}
impl UcaseFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("UCASE")
.with_return_type(ExprType::Text)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("expr"), vtype: ExprType::Text },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description(
"Returns a copy of a string with all letters converted to uppercase.",
)
.build(),
})
}
}
impl Callable for UcaseFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let s = scope.get_string(0).to_owned();
scope.return_string(s.to_uppercase())
}
}
/// The `VAL` function.
pub struct ValFunction {
metadata: Rc<CallableMetadata>,
}
impl ValFunction {
/// Creates a new instance of the function.
pub fn new() -> Rc<Self> {
Rc::from(Self {
metadata: CallableMetadataBuilder::new("VAL")
.with_return_type(ExprType::Double)
.with_syntax(&[(
&[SingularArgSyntax::RequiredValue(
RequiredValueSyntax { name: Cow::Borrowed("expr"), vtype: ExprType::Text },
ArgSepSyntax::End,
)],
None,
)])
.with_category(CATEGORY)
.with_description(
"Parses a string as a number.
Returns the numeric prefix of expr$. Leading whitespace is ignored, and if expr$ does not start \
with a number, this returns 0. Stops processing (without an error) at the first non-numeric \
character.",
)
.build(),
})
}
}
impl Callable for ValFunction {
fn metadata(&self) -> Rc<CallableMetadata> {
self.metadata.clone()
}
fn exec(&self, scope: Scope<'_>) -> CallResult<()> {
debug_assert_eq!(1, scope.nargs());
let s = scope.get_string(0);
let value = parse_numeric_prefix(s);
scope.return_double(value)
}
}
/// Adds all symbols provided by this module to the given `machine`.
pub fn add_all(machine: &mut MachineBuilder) {
machine.add_callable(AscFunction::new());
machine.add_callable(ChrFunction::new());
machine.add_callable(InstrFunction::new());
machine.add_callable(LcaseFunction::new());
machine.add_callable(LeftFunction::new());
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